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Tailored polyacrylonitrile (PAN) ultrafiltration (UF) membranes are fabricated with Pluronic-F127 and polyethylene glycol phosphate decorated calcium carbonate (PGP-CaCO3) additives with the aim of high water permeation, macromolecular rejection and antifouling properties. The nanoscale CaCO3 synthesis is carried out via a single step carbonization route using PGP as a hydrophilic modifier to introduce hydroxyl groups onto its surface. The topographies of the nanoparticles are investigated using X-ray diffraction (XRD) and transmission electron microscopy (TEM). PAN/PGP-CaCO3 mixed matrix membranes (MMMs) are fabricated via phase inversion method and examined by attenuated total reflectance-Fourier infra-red spectroscopy (ATR-FTIR), mechanical stability, thermo-gravimetric analysis (TGA) and scanning electron microscopy (SEM) to explore the changes in membrane properties due to the well-dispersed PGP-CaCO3 in the PAN membrane matrix. The UF performance of the membranes is investigated in terms of pure water flux, macromolecular rejection and antifouling property. The fouling resistance of membranes is assessed using bovine serum albumin (BSA) and humic acid (HA) as model foulants. The membrane loaded with 0.75 wt.% (M3) of PGP-CaCO3 manifested increased wettability with reduced surface free energy leading to a higher pure water flux of 366 L/m2 h. M3 also displayed a rejection of 93.9% for BSA and 93.2% for HA. The success of the modification can be confirmed as the membrane M3 exhibited lower flux decline and displayed a flux recovery ratio of 90.98% during HA filtration. The results demonstrated the potential use of PAN/PGP-CaCO3 membranes in water treatment.

Sulfonated poly(ether sulfone) (SPES) based proton exchange membranes (PEMs) are fabricated using sulfonated molybdenum disulfide (S-MoS2) nanosheets via facile solution casting method. SPES (DS = 30%) and S-MoS2 are synthesized and sulfonation is evidently observed in FTIR and XRD analysis. The anchoring of sulfonic acid group on exfoliated molybdenum disulfide (E-MoS2) and elemental composition of S-MoS2 are confirmed by XPS spectrum. Physico-chemical characteristics such as ion-exchange capacity (IEC), water uptake, swelling ratio and oxidation stability are found to be increases after the addition of S-MoS2 into SPES matrix. Increment in S-MoS2 content in SPES matrix decreases the surface contact angle due to the increase in hydrophilicity. Further, the dispersing ability of S-MoS2 in SPES matrix is evidently shown by an increase in surface roughness, tensile strength and thermal stability of the SPES/S-MoS2 nanocomposite membranes. On the whole, SPES/S-MoS2-1 membrane showed the highest proton conductivity of 5.98 × 10−3 Scm−1, selectivity of 19.6 × 104 Scm−3s, peak power density of 28.28 mWcm−2 and lesser methanol permeability of 3.05 × 10−8 cm2s−1. The strong interfacial interaction between SPES and S-MoS2 in nanocomposite membranes create strong hydrogen bond network to facilitate the proton conduction pathway via both vehicle and Grotthuss type mechanisms. Overall results suggested that the SPES/S-MoS2 nanocomposite membranes are superior and appropriate alternative for commercially high-cost Nafion® membranes for use in renewable direct methanol fuel cell (DMFC) devices.

Herein, the potential impact of tamarind seed polysaccharide (TSP) on the gelation nature and in vitro release of a particular drug, pilocarpine hydrochloride, from different poloxamer 407-based ophthalmic formulations were evaluated. The combination of TSP (0.5–1.5 wt%) and 18 wt% poloxamer (PM) solutions resulted in a significant improvement in gel elasticity under physiological conditions. The introduction of TSP to PM not only enhanced the viscosity of the gel, but also stimulated the gelation procedure. Due to the inclusion of TSP, the gel dissolution rate of the PM-based formulation was greatly reduced. The FTIR spectral analysis revealed the interaction between –OH groups of both polymers, resulting in a decline in the gelation temperature of the PM–TSP-based formulations. It was also detected in the cryo-SEM analysis that the pore size of the PM gel decreased and the depth of its pores increased with the inclusion of TSP. Furthermore, the in vitro release analysis indicated that the retention capacity of PM–TSP-based formulations was superior to that of the only PM-based formulation. The SEM study and the cell viability data demonstrated the biocompatibility and non-toxicity of TSP. Therefore, the designed formulation is fairly promising to be utilized as an in situ ophthalmic drug carrier.

Poly(vinylidene fluoride) (PVDF)/organically modified nanoclay composites using different amount of nanoclay have been prepared through solution route. The structural changes are determined through X-ray diffraction and Fourier transform infrared spectroscopy studies, which show the transformation from α to β-phase crystallization in presence of nanoclay. Polarised optical microscopic images show the changes of spherulite pattern into mesh like pattern in presence of nanoclay. Modulus of PVDF-nanocomposite increase with increasing the nanoclay content up to 4 wt.% and then slightly decreases under uniaxial tension and the improvement in mechanical responses are fitted with theoretical models. Tribological behaviour of PVDF nanocomposites is evaluated and found that nanoclay content upto 4 wt.% is effective in decreasing the wear and coefficient of friction of PVDF. Similarly, hardness of the nanocomposites also increases for clay content upto 4 wt.%. The nanoclay is working as reinforcing agent for PVDF and is improving its mechanical and frictional properties. Keywords: PVDF, Wear, Hardness, Morphology

Supported flat sheet polyvinylidene fluoride - polytetrafluoroethylene (PVDF-PTFE) nanocomposite membranes were fabricated for this study using the phase inversion process. Several characterization methods, such as scanning electron microscopy, atomic force microscopy, attenuated total reflectance - Fourier transform infrared spectroscopy, water contact angle, and liquid entry pressure of water (LEPw) measurements, were carried out on the prepared membranes, and vacuum membrane distillation (VMD) experiments were then applied to test membrane permeabilities. The cooperation of PTFE was demonstrated to have great potential in enhancing the permeate flux of PVDF membranes while maintaining an acceptable LEPw value. At a feed temperature of 30 °C and vacuum pressure 97.54 kPa, the VMD pure water permeates flux of the prepared nanocomposite membrane embedded with 40 wt% PTFE was 5.61 kg/m2·h, while that of pure PVDF membrane was 0.71 kg/m2 h. The salt rejection results of the prepared nanocomposite membranes were all above 99.9%. These results indicate the applicability of the PVDF-PTFE nanocomposite membranes supported on non-woven polyester fiber for desalination.

To improve the interfacial affinity and antifouling properties of polyphenylsulfone (PPSU) membrane, nano CuO/g-C3N4 (g-CN) sheets were synthesized via facile calcination route as one pot synthesis method. The uniformly assembled nanohybrid fillers, CuO on g-CN sheets were confirmed by using XRD, TEM, EDX and FTIR analysis. The non-solvent induced phase inversion technique was used to fabricate the nanohybrid ultrafiltration (UF) membranes by doping different concentration (0.5–1 wt.%) of nano CuO/g-C3N4 (g-CN) sheets within the PPSU matrix. The results of contact angle, atomic force microscopy, energy-dispersive X-ray spectroscopy reveal that surface structure and physico-chemical properties of nanohybrid membrane plays lead role in solute interaction and rejection compared to bare membrane, M0. Furthermore, the interfacial affinity of membrane was explored in detail via surface free energy, spreading coefficient, wetting tension and reversible work of adhesion analysis. Nanohybrid UF membrane, with 0.5% of the filler (M1) displayed remarkable permeation flux of 202, 131 L/m2/hr for pure water and protein solution, respectively while maintaining a high protein rejection (96%). Moreover, the exceptional dispersion of the nanosheets in the polymer matrix enhanced FRR (79%) and decreased the overall resistance of M1 compared to the pristine membrane (M0). Overall results suggest that the incorporation of nano sheets is a facile modification technique which improves the comprehensive membrane performance and holds a great potential to be further explored for water treatment.

Contamination of water with pollutants that are toxic and/or carcinogenic has led to serious and irreversible consequences to the quality and safety of the water that we consume on a daily basis. This has led to extensive research worldwide to find immediate and effective solutions to this problem. One such practically efficient solution is the treatment of contaminated water for the removal of added contaminants. Among the materials used for water treatment, adsorbents and photocatalysts have been used extensively since they are easy to fabricate, functionalize and use, and they demonstrate high removal efficiencies. Very recently, polythiophene and its derivatives, as well as modified composites of polythiophene and its derivatives, have emerged as extremely promising adsorbent and photocatalyst materials. These materials possess high charge density, surface area and a number of sites to interact and adsorb pollutants. Herein, the research progress achieved so far regarding the fabrication and application of these polythiophene-based adsorbents/photocatalysts toward water purification has been summarized.

Polyvinylidene fluoride (PVDF) was blended with multi-walled carbon nanotubes (MWCNTs) and MWCNTs/SiO2 nano-additives to fabricate nanocomposite vacuum membrane distillation (VMD) membranes for desalination. The effects of MWCNTs and MWCNTs/SiO2 integrated additives on the morphology and performance of the PVDF membrane were studied. When only MWCNTs were used, 2 wt% loading of MWCNTs to PVDF had the maximum effect on the improvement of VMD flux, due primarily to the enlargement and elongation of the finger-like pores. Then, one of three different SiO2 nanoparticles (NPs) (hydrophobic, superhydrophobic and hydrophilic) was further added to the membrane that already contained 2 wt% of MWCNTs. When the amount of SiO2 NPs was relatively low, VMD flux increased as a result of the synergistic effects between the two filler components, i.e. one is the increase of overall porosity by MWCNTs and the other is the growth of the macrovoids by SiO2 NPs. But among those two, the effect of MWCNTs was more dominant. Compared with the pristine PVDF membrane and the nanocomposite PVDF membrane with a single filler of MWCNTs, respectively, the flux increase by the addition of SiO2 was 292% and 55%. On the other hand, when a relatively large amount of SiO2 NPs was added, the effect of SiO2 NPs started to dominate. Especially, the asymmetric structure of the membrane disappeared, leading to low mechanical strength. All fabricated membranes exhibited great desalination potential with salt rejection as high as >99.97%.

Sulfonated poly (ether sulfone) (SPES) membranes are fabricated using polydopamine layered molybdenum disulfide (PDM) nanosheets. The exfoliated molybdenum disulfide (E-MoS2) nanosheets are subjected to surface coating with self-polymerization of dopamine and probed by FT-IR and EDAX analysis. Membranes are characterized by FT-IR, XRD, SEM, AFM, contact angle, water uptake, ion-exchange capacity, proton conductivity, methanol permeability, TGA, mechanical and oxidative stability. Characterization results confirmed that the SPES/PDM nanocomposite membranes are better than bare SPES and Nafion-212 membranes possibly due to the interface electrostatic attraction between amine groups (-NH2 and –NH-) of PDM with sulfonate (SO3−) group of SPES which create the strong acid-base pair. This result in the enhancement of the proton transport pathway in nanocomposite membranes and also the PDM reduces the methanol transport channels by generating the tortuous path. SPES/PDM-1 membrane exhibits the highest proton conductivity of 5.64 × 10-3 Scm-1, methanol resistivity of 2.23 × 10-8 cm2s-1 and selectivity of 22 × 104 Scm-3s. SPES/PDM membranes are displayed better thermal, mechanical and oxidative stability probably due to the uniform distribution of PDM on SPES matrix as evidenced by SEM images. Overall results confirmed that the SPES/PDM membranes will be an alternate to expensive Nafion in clean energy DMFC devices.

MnO2 nanospheres are prepared by simple hydrothermal technique, and their influence on the permeation, antifouling and contaminant removal properties of poly (ether imide) (PEI) ultrafiltration (UF) membranes is investigated by adding them at three different concentrations such as 0.5, 1.0 and 2.0 wt.% (designated as PEI-0.5, PEI-1 and PEI-2). The hydrophilic property of PEI/MnO2 membranes is investigated using contact angle and pure water flux measurements. The addition of MnO2 nanospheres reduces the contact angle to 60.8° and enhances the pure water flux to 129.8 Lm−2h−1 for PEI-1 membrane due to the increased surface hydrophilicity. SEM and AFM characterization revealed that the custom-made membranes showed noticeable changes in the formation of macrovoid, porosity and roughness parameters. During the separation of contaminants such as bovine serum albumin (BSA), humic acid (HA) and oil, the tailored membranes show enhanced rejection (between 96.8 and 99%) and flux recovery ratio (FRR) (between 95.5 and 99.5%) due to the improvement in hydrophilicity and formation of the water layer on the membrane surface proved their better rejection and antifouling capacity. Hydraulic resistance (14.7 kPa/Lm−2h−1) and tensile strength (5.58 MPa) results suggested that, the PEI-1 membrane showed better resistance to pressure and mechanical stress compared to the standard PEI membrane, due to the changes occurred in their morphologies. However, the additive loading limited at 2 wt.%, in order to avoid the negative effects of MnO2 nanospheres at higher concentrations.

In this work simulation results for the pore wetting of vacuum membrane distillation (VMD) are reported, considering heat and mass balance at liquid/vapor interface when steady state is achieved. Two cases were studied. In case 1, the system is in isothermal condition. In case 2, heat enters only from the pore inlet and is removed at the liquid/vapor interface as liquid vaporizes. The simulation has shown that the liquid/vapor boundary may remain inside the pore at the steady state condition, which means the partial pore wetting is possible. The significant temperature drop from the pore entrance to the liquid/vapor interface has also been predicted. It was found from case 2 simulation that VMD is possible in a wider range of pore radius, r, than the Laplace equation predicts. As well, the possibility of VMD for the contact angle (θ) below 90° was justified.

Research into the structure, synthesis and properties of nanoscale materials has increased at an enormous pace over the past decades since they have a wide variety of applications ranging from adsorption to separation processes in water treatment. A wide range of technologies such as adsorption, electrochemical, membrane filtration, and ion-exchange methods are productively used in water treatment and nanoparticles also find application in each of these fields. Water pollution by various toxic contaminants such as proteins, humic acids, and oils and the shortage of pure water have become the most serious environmental issues encountered worldwide. Recently, nanomaterial-incorporated polymeric ultrafiltration membranes have been used effectively in water treatment technologies to address these environmental issues. Herein, we concisely review the performances of membranes incorporated with a variety of nanomaterials. This review summarizes some very recent results and contributions achieved with nanomaterials to date in the emerging field of ultrafiltration membrane technology research. Further, this review discusses the methods for the incorporation of diverse nanomaterials and their influence in altering membrane properties to improve performance. Special emphasis is given to the hydrophilicity, mechanical and thermal stability, and antifouling and antibacterial activity of nanomaterials.

In this research work, novel perfluorooctanoic acid-modified melamine (PFOM) was synthesized as a hydrophobic filler using a facile one-pot synthesis. PFOM incorporating polyvinylidene fluoride (PVDF) solution was cast on a cellulose sheet to prepare a dual-layered membrane employing the phase-inversion technique for direct contact membrane distillation (DCMD) application. The influence of PFOM to tailor the dual-layered membrane performance was then investigated. The long perfluoro chain in PFOM hydrophobic fillers increased the surface roughness of the membranes due to its random overlapping with PVDF backbone, and these membranes exhibited a higher water contact angle value. The increase in pore size and membrane porosity did not significantly influence the liquid entry pressure of water (LEPw). The microporous membranes displayed good mechanical strength for use in the test setup. Pure water permeation was the highest (6.9 kg m−2 h−1) for membrane (M1) with 1 wt% of PFOM when tested with a simulated sea-water solution (3.5% w/v NaCl) in the direct contact distillation mode. These membranes also achieved the theoretical salt-rejection of 99.9%, thus confirming the potential of these membranes to be investigated for large scale membrane distillation (MD) applications like desalination of seawater.

In this work, novel positively charged NF membranes, decorated with aromatic amine moieties, aminated polyphenylsulfone (PPSU-NH2) were fabricated by the phase inversion technique. The prepared membranes were characterized by scanning electron microscopy, atomic force microscopy, average pore size and molecular weight cut-off. The surface properties of these membranes were determined by ion exchange capacity (IEC), contact angle (CA), surface free energy and water spreading coefficient. The membrane enriched with an aromatic amine (M3) had an overall smoother membrane surface with a pore size of 0.72 nm M3 has a positively charged surface with an IEC of 0.51 meq.g−1 and a highly hydrophilic nature confirmed by a low water CA (∼31°), and the greatest observed pure water flux (∼54 LMH). The amine incorporated membranes showed an increased resistance to fouling when challenged with cetyl trimethyl ammonium bromide as a model foulant, which suggests the existence of repulsive forces shielding the membranes from the positively charged foulants. The M3 showed a considerable rejection of 89 and 93.5% for the multivalent salts CaCl2 and AlCl3, respectively, and expectedly lower rejection of 18.7 and 25.6% for univalent salts Na2SO4 and NaCl, respectively. The prepared membranes demonstrated an exceptional ability in rejection (>99%) of cationic dye crystal violet while maintaining a moderate flux. Therefore, this method of preparation of a positively charged NF membrane can be further investigated for its potential for the removal of dyes and metal ions from commercial waste streams.

BACKGROUND: Ultrafiltration (UF) is a promising separation technique for the removal of macromolecular contaminants. However, the hydrophobic polymeric UF membrane performance suffers from fouling in the long run due to clogging by contaminants at the surface and pores. In this study, anti‐fouling hydrophilic polyacrylonitrile (PAN) UF membranes in the presence of an amphiphilic triblockcopolymer, Pluronic F127 (PF127) were prepared via a phase inversion technique. RESULTS: The effect of varying concentrations of PF127 on PAN UF membranes was analyzed by attenuated total reflectance–Fourier transform infrared spectroscopy (ATR‐FTIR), by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The filtration characteristics of the membranes were measured in terms of pure water flux, membrane porosity and water content. The separation efficiency of the membranes is explored for contaminants such as bovine serum albumin (BSA), humic acid (HA) and oil. The results revealed that the PAN membrane with 4 wt% of PF127 produced greatest permeate flux of 391 L m⁻² h⁻¹ with minimal fouling. A higher solute rejection of more than 90% was observed for the tailored membranes due to the improvement in surface properties. CONCLUSION: The inherent hydrophilicity of the high density poly (ethylene oxide) brush‐like layer of PF127 at the membrane–water interface is utilized effectively to restrict the adsorption of the organic contaminants onto the membrane surface. After simple hydraulic washing of PAN/PF127 UF membranes, the flux recovery ratio was augmented which is ascribed to their excellent antifouling property and potential use in water treatment. © 2018 Society of Chemical Industry

The environmental consequences of lead ion accumulation have been linked to detrimental health impacts in humans. Hence, removal of heavy metal (lead, Pb) ions by membrane adsorption/filtration was studied in this work using nanofibrous membranes in which the adsorbent metal-organic framework, MOF-808, was embedded. S-shaped breakthrough curves were obtained experimentally when the heavy metal concentration in the permeate was plotted vs the filtration period. Simple model equations that enable the reproduction of the S-shaped breakthrough curve were derived. It was found that the model equations could simulate the experimental data reasonably well. Attempts were further made to correlate the parameters involved in the model equations to the properties of mixed matrix nanofibrous membranes, including the pore size and pore size distribution, membrane thickness, fiber diameter, the adsorption rate constant, the Langmuir adsorption constant and the maximum adsorption capacity. The model equation parameters were also correlated to the operating conditions including the heavy metal concentration in the feed and the transmembrane pressure difference. It is believed that the model equations, despite this simplicity, can provide deeper insight into the membrane adsorption/filtration phenomena. These equations also contribute to the process design for successful removal of heavy metal ions from the environment to improve health factors for humans.

Nanostructured conducting polymers are known to function as electroactive materials in sensor devices for adsorption and detection of different analytes. For the purpose of dopamine (DA) detection and CO2 gas adsorption we have prepared nanostructured polypyrrole (PPY) with the help of sodium cholate as surfactant. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM) analyses and Brunauer–Emmett–Teller (BET) measurement have been done for the characterization of nanostructure and morphology of the prepared PPY. From the sorption measurement, it is observed that the rodlike PPY structures show highest N2 uptake (91.6 mL g−1) along with appreciable surface area (85.81 m2/g) and porosity (2.53 and 4.51 nm) values. It is also observed that the maximum uptake of CO2 is 173.885 mL g−1 at 195K for the PPY synthesized without any surfactant. Electrochemical characterization of PPY modified glassy carbon electrode (GCE) was done with impedance and cyclic voltammetry experiments. DA sensing in presence of ascorbic acid, uric acid and glucose was done by LSV technique. The PPY modified electrode exhibits sensitivity values of 0.301 and 0.19 μA μM−1 cm2 over two ranges of detection limits of 0.09–0.56 and 10–50 μM for dopamine, respectively (signal/noise = 3).

Thermoplastic and amorphous poly(ethylene terephthalate)/clay nanohybrids have been prepared through solution route. Organically modified NK75 nanoclay has been used as filler in different concentrations to enhance the properties. The Young’s modulus has increased significantly (66%) though there is slight reduction in toughness. Halpin Tsai and Hui-Shia models have been fitted well to explain the nature of stiffness for the prediction of the modulus values. Vicker hardness test has shown considerable improved hardness (16%) in nanohybrids and are nicely predicted using the modified rule of mixture model. The effect of uniaxial stretching on the structural development is explored through small angle X-ray scattering and wide angle XRD. The nanoclay has induced short range ordering upon stretching in nanohybrids as compared to pure PET. Nanoclay has induced high barrier for gas permeation in nanohybrids in comparison to pristine PET. Oxygen transmission rate has also been found to decrease up to 38% for using meager amount of nanoclay. The experimental permeability data has been fitted with different models and has been found suitable for its real applications.

Sulfonated poly (ether sulfone) (SPES) and poly (vinyl alcohol) (PVA) blend nanocomposite proton exchange membranes were fabricated and tailored with exfoliated tungsten disulfide (E-WS2) nanosheets with the aim of achieving better methanol resistant properties for direct methanol fuel cell (DMFC) applications. Reinforcement due to the existence of E-WS2 nanosheets on composite membrane imparted superior mechanical and thermal stability. Surface morphology of the composite membranes in terms of roughness is examined by AFM. Further, the results confirmed the intercalation of E-WS2 nanosheets onto the polymer matrix. The incorporation of E-WS2 nanosheets onto SPES/PVA system shows highest proton conductivity of 1.18 × 10−2 Scm−1 (at 25 °C) and mechanical stability of 143 MPa upon comparison with pristine SPES membrane. Furthermore, the methanol absorption by membrane matrix is found to be 3.42 × 10−8 cm2s−1. Overall results confirmed that SPES/PVA/E-WS2 nanocomposite proton exchange membranes are promising for applications in DMFCs.

Recently utilization of nanoparticle incorporated polymer membranes for water treatment is in significant consideration. Herein we present the individual effect of graphene oxide (GO) and molybdenum disulfide (MoS2) nanosheets in altering the poly (amide imide) (PAI) membrane's hydrophilicity and thereby its separation efficiency and antifouling ability. The GO was characterized by Field Emission Scanning Electron Microscope (FESEM) and Raman spectroscopy. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction spectroscopy (XRD) were used to probe the existence of GO and MoS2 in PAI nanocomposite membranes. Contact angle (CA), pure water flux (PWF), water uptake, and porosity were measured to evaluate the enhancement in hydrophilicity of nanocomposite membranes. Top surface and cross-section morphology of the membranes were investigated by scanning electron microscopy (SEM). Antifouling capacity of the membranes was evaluated by fouling experiments using bovine serum albumin (BSA) and humic acid (HA) fouling agents. PAI-MoS2 nanocomposite membranes demonstrated better results in enhancing the membrane performance viz., superior PWF (105.6 Lm−2h−1), water uptake (80%) and porosity (21.2%), BSA and HA rejection (95.8 and 93.2%), FRR (90.5%), and slightly reduced hydraulic resistance ( R m ) and more reduced CA (64.8°) than that of PAI-GO nanocomposite membranes. The highly flexible and ultrathin MoS2 nanosheets with greater interaction between Mo and S atoms causes larger macrovoids in the bulk, and the sandwiched structure of MoS2 causes greater permeation. GO also improved PAI matrix to some extent due to its oxygen containing functional groups however several desirable and versatile characteristics of the MoS2 makes the PAI-MoS2 UF membranes as superior performer.

Supported flat sheet nanocomposite polyvinylidenefluoride (PVDF) membranes embedded with hydrophilic TiO2, hydrophobic TiO2, or the combination of them were fabricated via phase inversion process. The membranes were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, atomic force spectroscopy, and the measurement of water contact angle and liquid entry pressure of water and subjected to tests on vacuum membrane distillation (VMD) performance. Addition of appropriate amounts of either hydrophilic or hydrophobic NPs was found to enhance VMD flux but hydrophilic NPs caused significant decrease of liquid entrance pressure of water (LEPw) while hydrophobic particles did not show significant impacts on LEPw. Addition of both hydrophilic and hydrophobic NPs demonstrated synergistic effects in terms of both enhanced flux and LEPw due to their different but complimentary effects on membrane structures. At feed temperature of 27.5 °C, the VMD pure water permeate flux of the composite membrane embedded with 5 wt% hydrophilic TiO2 NPs and 2 wt% of hydrophobic TiO2 NPs (total 7 wt% NPs) was 4.26 kg/m2h with a LEPw of 28 psi, while those of neat PVDF membrane, the membrane embedded with 7 wt% of hydrophilic NP, and the membrane with 7 wt% hydrophobic nanoparticles were 0.335, 3.57, and 1.25 kg/m2 h, respectively, and the LEPw of these membranes were 51, 24 and 47 psi, respectively. It is noted that at 5 wt% addition, the flux of M-L5 (hydrophilic NPs) is 3 times higher than the M-B5 (hydrophobic NPs). Furthermore, by adding another 2 wt% of NPs, flux increment by M-L5-B2 (hydrophobic NPs) is 3.5 times higher than M-L7 (hydrophilic NPs). Therefore, in both the effects combined, the highest flux was achieved by M-L5-B2 indicating synergistic effect of hydrophilic and hydrophobic NPs on the membrane flux. The salt rejection of above 99% could be maintained for 3 h by the membrane in which both hydrophilic and hydrophobic NPs were loaded. Numerical analyses of heat and mass transfer were also carried out to study the impact of hydrophilic and hydrophobic NPs on membrane characteristics.

An attempt has been made to demonstrate the effects of exfoliated tungsten disulfide (E-WS2) nanosheets on the fabrication, permeation and anti-fouling performance of cellulose acetate (CA) ultrafiltration membranes. The E-WS2 was prepared and characterized in terms of energy dispersive X-ray spectroscopy (EDXS) and X-ray diffraction spectroscopy (XRD). Pure and composite CA membranes were methodically characterized for its surface, chemical and morphological structure using FT-IR, XRD, SEM and water contact angle analysis. Filtration characteristics of membranes such as pure water flux, porosity and hydraulic resistance were also studied. The addition of E-WS2 nanosheets exhibited significant improvement in the surface hydrophilicity of composite membranes than the control CA membrane and are evidenced by the observed contact angle and porosity values. However at 1 wt% E-WS2 concentration, CA membrane showed lower water flux (92.3 ± 0.5) due to the pore plugging effect. The flux recovery ratio (FRR), bovine serum albumin (BSA) rejection, reversible and irreversible fouling experimental results suggested that CA/E-WS2 (1 wt%) UF membranes possess better fouling resistance potential than control CA membrane as a result of enhanced hydrophilicity. This study emphasizes the strong interplay between CA and E-WS2 nanosheets which play a significant role in altering the permeation and antifouling characteristics of nanocomposite membranes.

Exfoliated molybdenum disulfide (E-MoS2) incorporated sulfonated poly ether sulfone (SPES) nanocomposite proton exchange membranes (PEMs) were made by solution casting method. E-MoS2 was synthesized from bulk MoS2 powder by ultrasonication and SPES was prepared by sulfonation of PES using sulfuric and chlorosulfonic acid. Surface characterization of these membranes have been performed using several techniques such as Fourier transformed infra-red spectroscopy, x-ray diffraction, atomic force microscopy, scanning electron microscopy and contact angle measurements. In order to assess the physicochemical performance of the membranes, water uptake, swelling ratio and ion exchange capacity (IEC) of the membranes were measured. Thermal and mechanical stability of the nanocomposite PEMs were probed by thermogravimetric, analysis and tensile strength measurement respectively. Physicochemical characteristics such as water uptake, IEC, swelling ratio, thermal and mechanical stability of SPES/E-MoS2 nanocomposite PEMs were increased upon comparison with the bare SPES PEM. Tensile strength of SPES-1 nanocomposite PEM (117 MPa) is doubled upon comparison with pure SPES PEM (60 MPa). AFM images of PEMs nanocomposite revealed that surface roughness and nodular size were increased upon the addition of E-MoS2. Electrochemical performance of nanocomposite membranes such as proton conductivity, selectivity and methanol permeability were investigated and results confirmed that SPES/E-MoS2 nanocomposite membranes exhibited better performance than bare SPES PEM. More specifically, SPES membrane incorporated with 1 wt% E-MoS2 (SPES-1) exhibited higher proton conductivity (3.17 × 10−3 Scm−1), selectivity (8.43 × 104 Scm−3s) and lower methanol permeability (0.376 × 10−7 cm2s−1). From the results, it is evident that SPES-1 PEM nanocomposites are better candidate for applications in DMFCs.

A series of poly (vinylidene fluoride-co-hexafluoropropylene)/phosphotungstic acid/polypyrrole [SPVdF-co-HFP/PWA/PPY- n, where ‘n’ denotes the number of times the PPY coating process was repeated] composite proton exchange membranes (PEMS) were fabricated and studied for its suitability in direct methanol fuel cells (DMFCs). In situ polymerization was used for the lamination of polypyrrole (PPY) on the SPVdF-co-HFP/PWA membrane surface to diminish the leaching of phosphotungstic acid (PWA). FT-IR analysis confirmed the blending of PWA to SPVdF-co-HFP and the coating of PPY on the composite PEM. AFM study indicated that the surface roughness of the composite membrane was decreased by increasing in PPY layer. Ion exchange capacity, water uptake and swelling ratio of the SPVdF-co-HFP/PWA membranes were decreased whereas tensile strength was increased by increasing the PPY layer. The hydrophobic PPY leads to a substantial drop in methanol crossover with workable levels of proton conductivity. The methanol crossover of SPVdF-co-HFP/PWA/PPY-5 hybrid PEM was found to be 1.73 × 10−7 cm2s−1 and was much lower than Nafion-117 (63 × 10−7 cm2s−1). The selectivity ratio of SPVdF-co-HFP/PWA/PPY-5 was found to be high (2.77 × 104 Scm-3s). Thus, all the experimental results revealed that the SPVdF-co-HFP/PWA/PPY composite membrane could be an alternative to high-priced Nafion.

Electrospun nanofiber composite membranes containing water-stable metal-organic frameworks (MOFs) particles (Zr-based MOF-808) supported on polyacrylonitrile (PAN) nanofiber synthesized via co-electrospinning have been prepared. MOF particles were dispersed in the organic polymer, and their subsequent presence was inferred by scanning electron microscopy. Membrane performance in heavy metal ion adsorption in batch filtration was evaluated on the basis of Cd2+ and Zn2+ ions sequestration. The adsorption capacities of the pristine MOF and the MOF composite membrane revealed that MOF particles in the membrane could be accessed for adsorption in the hydrophilic PAN membranes. The maximum adsorption capacities were 225.05 and 287.06 mg g–1 for Cd2+ and Zn2+, respectively. Conventional thermal activation of pristine MOF and composite membrane revealed a crystal downsizing, while “hydractivation” produced an expanded MOF with enhanced adsorption potentials. The PAN/MOF-808 “hydractivated” composite membrane coul...

Development and commercialization of alternative energy harnessing and storing devices are most necessarily required in today's world. Progressive increase in consumption of energy by the ever-incr...

Non-toxic nanocomposites based bio-films obtained from methylcellulose (MC) can reduce environmental problems associated with synthetic polymers. A new facile route for the isolation of cellulose nano-crystals (CNC) from jute waste is successfully utilized here. The fabrication of CNC reinforced MC nanocomposites by film casting technique and the studies of the effect of CNC on the properties of the MC based nanocomposites have been reported. The synthesized nanocomposites have shown improved UV resistance, mechanical, barrier, and thermal properties. FTIR results established the physicochemical compatibility between the drug, MC and CNC in nanocomposites. In vitro permeation studies performed by using Franz diffusion cell revealed diffusion mediated sustained drug release from the devices due to the presence of interaction between MC and CNC through H-bonding, electrostatic interaction between the hydrophilic polymer/CNC chains with the drug and the formation of tortuous path. The nanocomposites can be used for edible packaging and transdermal drug delivery.

Poly (m-phenylene isophthalamide) (PMIA) ultrafiltration (UF) membranes has been prepared using lithium chloride (LiCl) and poly (ethylene glycol) of average molecular weight 600 Da (PEG 600) as additives by phase inversion technique. Membranes were characterized by FTIR, TGA, DTG and UTM. Surface characteristics are probed by SEM, AFM and water contact Angle. It was evidenced from SEM analysis that all membranes have macrovoids in its structure and hence possess high water permeability. Accordingly, all membranes were highly hydrophilic in nature which can be predicted from water wettability and work of adhesion measurement using contact angle. Further, membranes were subjected for protein rejection study using bovine serum albumin (BSA) as a model foulant and its fouling ability was analyzed. It has been found that the 10 wt.% PMIA membrane with 2 wt% of PEG 600 and 4 wt.% of LiCl has high water permeability and better reversible and irreversible antifouling capability than any other prepared membranes. Flux recovery ratio (FRR) of 91% was obtained for the 10 wt.% PMIA also confirmed it is one of the promising UF membrane materials.

There is a need for reuse of waste cotton lint (WCL) from the blow room of yarn spinning mills. The drive to use this material for the synthesis of nanocellulose is difficult because of the several purification/pretreatment processes. Here, we developed a combined single bath purification process of WCL and utilized it for the synthesis of nano-crystalline cellulose crystals (NCs) which are valuable nanomaterials with novel properties along with acid recovery for reuse. The micrograph of the synthesized NCs confirmed a network of nano-sized crystalline cellulose crystals having nano ranged diameter of NCs isolated by two processes. The FTIR result established the removal of impurities and hemicelluloses from WCL. The crystallinity index of WCL (∼89.97%) is improved to ∼96% and ∼94% for sulphuric acid and nitric acid synthesized NCs (NC1 and NC2). The crystallite size of WCL, CTWCL, NC1, and NC2 was calculated using XRD and found to be 101.56, 103.54, 98.81, and 95.6nm respectively. The hydrodynamic size (Z-average) (dnm), polydispersity index and zeta potential of NCs was also studied using dynamic light scattering (DLS). The thermal stability of the NC1 is better than that of NC2. These NCs can be used as reinforcing filler/barrier material.

An attempt of studying the effects of the Pluronic F127 (triblock-co-polymer) and pore forming PEG 600 [poly (ethylene glycol) of average molecular weight 600 Da] additives in enhancing the hydrophilicity and antifouling properties of poly (amide imide) (PAI) ultrafiltration (UF) membranes was made. PAI membranes were fabricated by the addition of optimized amount of 5 wt.% of Pluronic F127 and PEG 600 additives individually via phase inversion technique and characterized in terms of scanning electron microscopy (SEM), contact angle (CA),work of adhesion (ωA), Fourier transform infrared spectroscopy (FT-IR), pure water flux (PWF), hydraulic resistance (Rm) and percent water content (%WC). Percent solute rejection (%SR) and permeate flux were measured using BSA (bovine serum albumin) and HA (humic acid) as modal fouling agents. Antifouling capacity of the membranes were studied by the experiments such as flux recovery ratio (FRR), reversible fouling (Rr) and irreversible fouling (Rir). The results obtained from the above mentioned characterizations revealed that the PAI/Pluronic F127 membrane exhibits better performance than that of PAI/PEG 600 membrane due to the dual performance of Pluronic F127 as pore former as well as hydrophilic surface modifier causes superior enhancement in the membrane hydrophilicity. Moreover, the strong interactions between the PAI and PEG 600, limits the performance of PAI/PEG 600 membrane. Hence, Pluronic F127 has a greater influence in effectively modifying the PAI membrane than PEG 600.

Sulfonated poly (vinylidenefluoride-co-hexafluoropropylene) (SPVdF-co-HFP) based polymer nanocomposite proton exchange membranes (PEMs) were successfully fabricated in the presence of sulfonated graphene oxide (SGO) as nano-filler for direct methanol fuel cell (DMFC) applications. Sulfonation of GO was carried out using sulfanilic acid and the incorporation of -SO3H groups were confirmed by FTIR, HR-TEM and Raman spectroscopy. The physicochemical properties of the fabricated membranes such as ion exchange capacity (IEC), water uptake (WU), swelling ratio (SR), oxidative, thermal and mechanical stability, proton conductivity, methanol permeability and membrane selectivity were determined. Among the various nanocomposite PEMs were prepared, SPVdF-co-HFP/SGO-7 exhibited good tensile strength (29.7 MPa), improved Young's modulus (432.5 MPa), high proton conductivity (5.52 × 10−3 S/cm, at 30 °C), superior selectivity (2.99 × 104 Scm−3s) and reduced methanol cross-over (1.846 × 10−7cm2s−1) and this nanocomposite membrane can possibly be a superior and alternate candidate to Nafion membrane in DMFCs.

Cellulose acetate (CA) nanocomposite ultrafiltration (UF) membranes were fabricated using 2D layered nanosheets such as graphene oxide (GO) and exfoliated molybdenum disulfide (E-MoS2) and effectively used for the removal of macromolecular protein. The GO and E-MoS2 nanosheets were prepared and characterized by FT-IR and XRD respectively. GO and E-MoS2 (0.5wt.%) were blended individually with CA. The assenting changes generated by the incorporation of GO and E-MoS2 in terms of surface hydrophilicity of the nanocomposite membrane were analyzed by pure water flux (PWF) and contact angle measurement. The influence of 2D nanosheets on the morphology of CA are studied by scanning electron microscopy (SEM). Mechanical strength and hydraulic resistance of the nanocomposite membranes were found to be improved compared to bare CA membrane. The separation and antifouling performance of the nanocomposite membranes were studied using macromolecular bovine serum albumin (BSA). From the results, it was observed that a CA/GO-0.5 membrane exhibited the highest PWF (125.4±1.7Lm-2h-1), water content (70.6±1.2%), porosity (34.6±1.7%), flux recovery ratio (FRR) (88.8±1.6%) and lowest contact angle (63.9±2.5°), hydraulic resistance (4.3±0.67kPa/Lm-2h -1) than pure CA and CA/E-MoS2-0.5 membranes. CA/GO-0.5 membrane displayed superior UF and antifouling performance due to the greater affinity of GO nanoparticles towards water.

Nowadays, bio-derived cellulose nano-fibrils based nanocomposites is gaining utmost interest in the area of barrier films for food packaging, as reinforcing filler to make biodegradable nanocomposites with different biopolymers for various applications such as transdermal drug delivery, edible packaging and tissue scaffolding. Ultrasound-assisted preparation of hydroxypropylmethylcellulose based nanocomposites with cellulose nano-fibrils were carried out following solution mixing technique. The crystalline nature of cellulose nano-fibrils has been scrutinized by X-ray diffraction study. The field emission-scanning electron micrographs of cellulose nano-fibrils revealed a network of nano-fibrillar morphology. The Fourier transform infrared spectroscopy results of cellulose nano-fibrils confirmed the removal of lignin and hemicellulose from raw jute (Corchorus olitorius L.) fibres. The storage modulus and tensile properties of hydroxypropyl methylcellulose films increased up to the addition of 1.00 wt% cellulose nano-fibrils. The moisture affinity of hydrophilic hydroxypropylmethylcellulose has also been reduced at 1.00 wt% cellulose nano-fibrils loading. The impact of cellulose nano-fibrils loading on the cumulative percentage of drug release from prepared nanocomposites films has been explored accordingly. By utilizing these versatilities of cellulose nano-fibrils, the fabricated nanocomposites are expected to be highly promising in the area of packaging and transdermal drug delivery system.

Herein, we report the effect of the exfoliated molybdenum disulfide (eMoS2) nanosheets in improving the permeability and anti-fouling properties of the PEI ultra-filtration (UF) membrane using bovine serum albumin (BSA) and humic acid (HA) as model fouling agents. The PEI/eMoS2 nanocomposite membranes were prepared via phase inversion method using three different eMoS2 concentrations (0.5, 1 and 2wt%) designated as PEI-0.5, PEI-1 and PEI-2, respectively. Fourier transform infra-red spectroscopy employed to probe the surface functionalities on the membranes. Contact angle measurement, pure water flux, swelling rate and solute rejection studies confirmed the improved hydrophilicity of the PEI/eMoS2 nanocomposite membranes than the individual entities. Flux recovery ratio (FRR), reversible and irreversible fouling results evidenced the improved fouling resistance of PEI/eMoS2 modified membranes than the individual counterparts. SEM results evidenced that the nanoscale eMoS2 significantly altered the membrane morphology by causing increased porosity and larger macrovoids formation on the surface as well as in the bulk of the membrane. PEI-1 membrane showed an increased pure water flux (52.54Lm-2h-1) and water content (74.8%) whereas lesser contact angle (69.2°) and hydraulic resistance (1.85kPa/Lm-2h-1). Resistance to fouling performance of PEI-1 membrane was evident from the FRR values of 95.3 and 90.2% and rejection values of 94.5 and 92.4% for BSA and HA respectively. PEI-2 membrane agglomerates with eMoS2 and hindered the membrane permeability by blocking the macrovoids in the bulk which restricted the permeation and fouling resistance of the membrane. Amongst various nanocomposite membranes investigated, the PEI-1 membrane exhibited better hydrophilicity and fouling resistance properties due to the availability of the favorable surface and bulk characteristics.

Nanotechnology has acquired an immense recognition in cancer theranostics. Considerable progress has been made in the development of targeted drug delivery system for potent delivery of anticancer drugs to tumor-specific sites. Recently, multifunctional nanomaterials have been explored and used as nanovehicles to carry drug molecules with enhanced therapeutic efficacy. In this present work, graphene oxide quantum dot (GOQD) was conjugated with folic acid functionalized chitosan (FA-CH) to develop a nanocargo (FA-CH-GOQD) for drug delivery in cancer therapy. The synthesized nanomaterials were characterized using Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, scanning electron microscopy, transmission electron microscopy, and dynamic light scattering. Photoluminescence spectroscopy was also employed to characterize the formation of GOQD. To validate the efficacy of FA-CH-GOQD as nanocarriers, doxorubicin (DOX) drug was chosen for encapsulation. The in vitro release pattern of DOX was examined in various pH ranges. The drug release rate in a tumor cell microenvironment at pH 5.5 was found higher than that under a physiological range of pH 6.5 and 7.4. An MTT assay was performed to understand the cytotoxic behavior of GOQD and FA-CH-GOQD/DOX. Cytomorphological micrographs of the A549 cell exhibited the various morphological arrangements subject to apoptosis of the cell. Cellular uptake studies manifested that FA-CH-GOQD could specifically transport DOX within a cancerous cell. Further anticancer efficacy of this nanomaterial was corroborated in a breast cancer cell line and demonstrated through 4',6-diamidino-2-phenylindole dihydrochloride staining micrographs.

Two major problems in chemotherapy, poor bioavailability of hydrophobic anticancer drug and its adverse side effects causing nausea, are taken into account by developing a sustained drug release vehicle along with enhanced bioavailability using two-dimensional layered double hydroxides (LDHs) with appropriate surface charge and its subsequent embedment in polymer matrix. A model hydrophobic anticancer drug, raloxifene hydrochloride (RH), is intercalated into a series of zinc iron LDHs with varying anion charge densities using an ion exchange technique. To achieve significant sustained delivery, drug-intercalated LDH is embedded in poly(ε-caprolactone) (PCL) matrix to develop intravenous administration and to improve the therapeutic index of the drug. The cause of sustained release is visualized from the strong interaction between LDH and drug, as measured through spectroscopic techniques, like X-ray photoelectron spectroscopy, infrared, UV-visible spectroscopy, and thermal measurement (depression of melting temperature and considerable reduction in heat of fusion), using differential scanning calorimeter, followed by delayed diffusion of drug from polymer matrix. Interestingly, polymer nanohybrid exhibits long-term and excellent in vitro antitumor efficacy as opposed to pure drug or drug-intercalated LDH or only drug embedded PCL (conventional drug delivery vehicle) as evident from cell viability and cell adhesion experiments prompting a model depicting greater killing efficiency (cellular uptake) of the delivery vehicle (polymer nanohybrid) controlled by its better cell adhesion as noticed through cellular uptake after tagging of fluorescence rhodamine B separately to drug and LDH. In vivo studies also confirm the sustained release of drug in the bloodstream of albino rats using polymer nanohybrid (novel drug delivery vehicle) along with a healthy liver vis-à-vis burst release using pure drug/drug-intercalated LDHs with considerable damaged liver.

Fe(III) and Zr(IV) based metal–organic frameworks (MOFs) were enmeshed in polyacrylonitrile (PAN) and polyvinylidene fluoride (PVDF) electro-spun nanofibers to produce nanofibrous MOF membranes (NMOM). The pristine MOFs showed high adsorption capacity for lead ions and mercury ions from aqueous solution. The Fe(III) based MOFs with PAN based NMOM exhibited a high flux of 348 L m−2 h−1 with a permeance of 870 L m−1 h−1 bar−1. At room temperature, the NMOM could treat 395 mL of 100 ppb Pb(II) solution, while maintaining a drinking water standard of

Manganese dioxide (MnO2) nanospheres were prepared by a facile hydrothermal technique and their influence on the permeation and antifouling properties of poly(vinylidene fluoride) (PVDF) ultrafiltration (UF) membranes was investigated. Different concentrations of MnO2 nanospheres (such as 0.0, 0.5, 1.0 and 2.0 wt%) were added and they were designated as pristine PVDF, PVDF-0.5, PVDF-1 and PVDF-2, respectively. AFM images confirmed that upon increasing the wt% of MnO2 nanospheres, there is an increase in the surface roughness of the PVDF/MnO2 nanocomposite membranes. Further, SEM images revealed the formation of finger-like macrovoids along with improved porosity. Moreover, upon increasing the wt% of MnO2 on PVDF, the pure water flux was enhanced and attains a value of 153.4 Lm−2 h−1 for the PVDF-2 nanocomposite membrane. Fouling experiments were performed using bovine serum albumin (BSA) and humic acid (HA) as model fouling contaminants. Experimental results confirmed that the higher flux recovery ratio (FRR) of the PVDF/MnO2 membranes indicates the enhancement of their hydrophilicity and antifouling ability. Tensile strength results suggested that the PVDF/MnO2 membranes possess improved mechanical resistance compared with the pristine PVDF due to the change in their morphologies. However, increasing the concentration of MnO2 beyond 2% resulted in phase inversion during membrane fabrication and hindered the membrane formation. The results confirmed that the PVDF-2 membrane outperformed other membranes employed in this work in terms of improved permeation and antifouling properties, without compromising the BSA or HA rejection and membrane strength. In light of all these results, it is evident that the MnO2 nanosphere incorporated PVDF nanocomposite UF membrane shows potential for water treatment applications.

The delivery of diltiazem hydrochloride in therapeutical doses has attracted an immense research interest. However, its slower penetration through the transdermal route has stipulated to develop a competent transdermal membrane. Therefore, a nanocomposite based patch was formulated by exploring co-polymer and jute derived nano-cellulose. Poly(N-isopropylacrylamide) was grafted into guar gum (GG-g-PNIPAAm) with different feeding ratios. The co-polymer formation was authenticated by FTIR and 13C NMR spectra. The nanocomposite were prepared by incorporating nanofibre (0.5–2 wt%) into GG-g-PNIPAAm. The structural and morphological studies supported good interactions and presence of nano-cellulose on co-polymer. GG-g-PNIPAAm has showed higher thermostability than guar gum. Moreover, the addition of CNF has improved the thermo-mechanical and barrier properties of the nanocomposite. The nanocomposite containing 1 wt% CNF was found to be best performing. The patch showed in-vitro cyto-compatibility and non-irritant behaviour. The in-vitro release study of best nanocomposite revealed controlled drug release capability with 7.78 and 22.9% after 5 and 20 h, respectively.

Membrane technologies have been successfully developed as the separation and purification processes, such as desalination, wastewater treatment, gas separation and so forth. It is known that membrane pore size and pore size distribution (PSD) are the factors by which membrane performance is significantly affected. In this study, a novel mathematical model is presented to evaluate the PSD. Although the new model is based on the bubble gas transport method, it is different from the conventional approach since this model starts from the assumption of a distribution function, typically Gaussian normal distribution, for the PSD, and a flow rate versus pressure line is drawn theoretically based on the assumed PDS. Then, the mean pore size and standard deviation of the PSD are optimized by the best fit of the theoretical line to the experimental one using the nonlinear regression analysis. A unique feature of the proposed model is that fewer experimental data points are necessary to find the optimal PSD. In addition, experiments with the dry membrane are no longer required. The PSDs estimated by this model for three commercial membranes were compared with those obtained by the conventional method, and an excellent agreement was observed.

Thermoplastic polyurethane (TPU) nanohybrids have been prepared through melt extrusion using ester type PU and different concentrations of Indian origin organically modified nanoclay as filler. The level of dispersion of nanoclay in TPU is found to be good and considerable intercalation occurs due to strong interaction between polymer matrix and filler. The interaction is shown through spectroscopic measurement from the shifting of peak position in FTIR and UV–vis. absorption spectra. Nanoclay induces crystallization in polymer while the blob size, as measured through small angle neutron scattering, decreases in nanohybrid (1.5 nm) as compared to pure TPU (1.7 nm) obtained after fitting the initial data point to Debye-Bueche model. Mechanical responses are much superior in nanohybrid as compared to pure TPU and stiffness values continue to increase with nanoclay concentration while the toughness reach ata maximum value at an optimum concentration of 4 wt% of nanoclay. Uniaxial stretching lead to the crystallization of segments and ordering of hard segments as verified through sharp melting points in stretched TPU vis-a-vis predominant amorphous nature before stretching. Nanohybrid membranes are prepared to investigate the gas permeation across the membranes and very high gas barrier of nanohybrid (449 Barrer) is found as opposed to pure TPU barrier of 169 Barrer. Critical assessment of permeability is performed in presence of nanoclay in different concentrations with a plausible mechanism of gas barrier.

The effect of gellan gum on the gelation behavior and in-vitro release of a specific drug named pilocarpine hydrochloride from different ophthalmic formulations based on poloxamer 407 is examined. The mixture of 0.3wt% gellan gum and 18wt% poloxamer (PM) solutions show a considerable increase in gel strength in physiological condition. Gel dissolution rate from PM based formulation is significantly decreased due to the addition of gellan gum. FTIR spectra analysis witnesses an interaction in between OH groups of two polymers which accounts for lowering in gelation temperature of PM-gellan gum based formulations. It is also observed from the cryo-SEM study that the pore size of PM gel decreases with an addition of gellan gum and in-vitro release studies indicate that PM-gellan gum based formulation retain drug better than the PM solution alone. Therefore, the developed formulation has the potential to be utilized as an in-situ ophthalmic drug carrier.

Graphene oxide (GO) was synthesized and used as an additive at various proportions with the intention of fabrication of sulfonated poly (ether sulfone) (SPES) based composite proton exchange membranes (PEMs) for direct methanol fuel cell (DMFC) applications. Among the various composite membranes prepared, SPES/GO (1 wt%) was found to have the highest selectivity with a water uptake of 40.1%, proton conductivity of 4.3 × 10 −3 S/cm, and methanol permeability of 4.923 × 10 −8 cm 2 /s. The introduction of GO in membranes not only improved proton conductivity, but also positively affected the mechanical properties and the blocking of methanol molecules passing through the membrane. Consequently, the incorporation of GO into SPES membrane has considerably increased the selectivity of the membrane. Therefore, SPES/GO membranes showed three folds increase in performance than original SPES membrane, and hence acted as a good candidate for use in DMFC in order to resolve current issues of methanol crossover.

In this paper, we report the mechanism of electrical transport properties of polyaniline coated Ti0.9Al0.1C prepared by chemical route. Samples are characterized by X-ray diffraction technique and morphology has been observed by field emission scanning electron microscope. Semiconducting behavior is obtained for the samples and this behavior has been analyzed by different existing models. Out of different models the Mott’s variable range hopping is the most suitable for analyzing the dc conductivity at lower temperatures. Correlated barrier hopping type of charge transfer process is followed in alternating current conductivity. We observe a transformation from negative to positive dc and ac magnetoconductivity by incorporating Ti0.9Al0.1C in polyaniline. Dielectric properties and impedance analysis are described by Maxwell–Wagner capacitor model. We determine different parameters like localization length, hopping distance, density of states from the analysis of the experimental data. The theory regarding magnetic field dependent ac conductivity is insufficient. This result will be a significant hint for a new theoretical challenge.

Proflavine, a nitrogen-containing dye is used for DNA staining and as an efficient marker, however, it is harmful to body cells, and its efficient removal is essential. In this work, graphene oxide (GO) has been used as an adsorbent for the removal of the dye through the process of adsorption. Though GO is now being used as an adsorbent for the removal of industrial dyes, very few experiments have been done on biologically useful dyes. GO is synthesized from graphite powder by the modified Hummer's method and is characterized by X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), Raman and ultra-violet spectroscopies, etc. These characterization techniques indicate the presence of oxygen containing functional groups, e.g., carbonyl, carboxyl and hydroxyl groups on the graphene sheets. These sheets are held well apart by these groups. Parameters like concentration of the adsorbent, pH and temperature have been varied to find the optimum conditions for the most efficient removal of the dye molecules from the solution. Then, for the optimum external conditions, the time dependence of the adsorption was analyzed using pseudo-first and pseudo-second orders kinetics. The adsorption isotherms were also obtaining throws light on the mechanism of the adsorption process which we investigated further by using FTIR characterization.

A diverse nanostructure, key to property alteration, has been observed by the insertion of two dimensional nanoparticles through in-situ polymerization. Self-assembly at the molecular level has been revealed starting from nanoscale to observable microscale in thermoplastic polyurethane using alicyclic diisocyanate and how the self-assembly behaviour changes in presence of nanoparticle. Varying dispersion of nanoparticles observed using two different fillers has been explained from the interactions point of view through spectroscopic techniques. Thermal stability and unique crystallization behaviour have been reported in presence of nanoparticles. Better dispersion of nanofillers within the matrix offers greater number of nucleating site which enhances the ordering of the polymer chains, also supported by the semi-empirical calculation. The effect of modulated nanostructure and self-assembly augmented the shape memory behaviour in polyurethanes having alicyclic diisocyanate. Enhanced shape recovery has been observed in presence of organically modified clay as opposed to layered double hydroxide. The reason for this improved shape memory behaviour in nanohybrid is explained from the exclusive crystallization of the soft segment domain leading to a proposed model for shape recovery. Finally, the recovery of different shapes (coil, spinal and straight strip) at physiological temperature (37 °C) has been demonstrated, added advantage of these materials to be used in the biomedical applications.

Cellulose nanofibrils (CNFs) have attracted attention as a promising material in the biomedical field because of their outstanding properties such as hydrophilicity, biocompatibility, biodegradability, and high surface area. In this work, we have prepared cellulose nanofibrils from jute fibres (JF), to develop a CNF/chitosan transdermal film for the delivery of ketorolec tromethamine (KT) where the CNFs act as an elegant nanometric carrier. The KT-loaded CNF/chitosan transdermal film matrices have been characterized by Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. Fourier transform infrared spectroscopy (FTIR) reveals the successful KT loading into the CNF/chitosan transdermal film. Scanning electron microscopy (SEM) study shows the different morphological features of the CNF/chitosan transdermal films. The crystalline nature of the CNF/chitosan transdermal films has been analyzed by X-ray diffraction study. Release profiles from the CNF/chitosan matrices indicate that the drug release rate is sustained with the incorporation of CNFs. We believe that this new nanocarrier may be a potential choice for transdermal drug delivery systems.

Exfoliated molybdenum disulfide (E-MoS2) nanosheets were synthesized from bulk MoS2. Poly(vinylidene fluoride) (PVDF) was incorporated into E-MoS2 to yield nanocomposite ultrafiltration (UF) membranes by the phase inversion technique. Various proportions of E-MoS2 (0.1, 0.5 and 0.8 wt%) were prepared and were characterized in terms of permeation and antifouling properties. FT-IR and XRD studies confirmed the presence of E-MoS2 in the membranes. Moreover, SEM and FESEM/EDX analysis of the membranes confirmed the increase in the porosity and presence, respectively, of E-MoS2. Atomic force microscopy (AFM) images confirmed that the membrane with 0.5 wt% E-MoS2 exhibited a uniform surface structure with (Ra = 35 nm), compared to the pure PVDF membrane (Ra = 37.6 nm). In addition, the membrane with 0.5 wt% E-MoS2, exhibited higher pure water flux (PWF) (105.1 L m−1 h−1), water content (73.7%), porosity (12.24%), bovine serum albumin (BSA) solute rejection (92.3%), least mechanical stability (1.13 MPa), hydraulic resistance (7.44 kPa L−1 m−2 h−1) and contact angle (72.8°). From all these, it is evident that the overall PVDF membrane performance was enhanced by the E-MoS2 addition, and the membrane with 0.5 wt% E-MoS2 outperformed the other counterparts due to its versatile characteristics and superior potential in the water treatment.