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AbstractIntermolecular hydrogen bonding plays a pivotal role in the stability and efficacy of drug-polymer mixtures, which are essential components in modern drug delivery systems. The knowledge of prominent interactions might provide a means to optimize the physiochemical stability of the developed targeted system. Hence, this review explores the fundamental principles of hydrogen bonding in drug-polymer interactions which can significantly influence the solubility, stability and release profiles of pharmaceutical formulations. The review provides an in-depth examination of the types of functional groups that participate in hydrogen bonding, the characterization techniques employed to study these interactions and the implications of hydrogen bonding on drug delivery. Case studies of successful drug-polymer systems stabilized by hydrogen bonding are presented, highlighting the practical applications and challenges associated with these formulations. Furthermore, the review discusses the future perspectives in this field, including the design of novel polymers and the integration of computational modeling to predict hydrogen bonding behavior. By understanding and leveraging hydrogen bonding, researchers can optimize drug delivery systems, ensuring enhanced bioavailability, controlled release and improved patient outcomes. This review aims to serve as a comprehensive resource for pharmaceutical scientists and formulators, offering insights into the strategic use of hydrogen bonding to develop more effective and stable drug delivery systems. [ABSTRACT FROM AUTHOR]

Protein-based fish adhesives have historically been used in various bonding applications; however, due to the protein's high affinity for water absorption, these adhesives become destabilized in high-moisture environments, resulting in reduced bondline strength and early failure. This limitation makes them unsuitable for industrial applications with higher demands. To address this issue, water-insoluble raw powder materials such as iron, copper, or zeolite were incorporated into natural fish adhesives. In this study, the hygroscopicity, dry matter content, thermal analysis (TGA/DSC), FT-IR spectroscopy, surface tension measurements, vapour permeability, and scanning electron microscope (SEM) of the modified adhesives were determined. In addition, the bonding properties of the modified adhesives were evaluated by the tensile shear strength of the lap joints, and mould growth was visually inspected. The resulting modified protein-based adhesives demonstrated improved stability in high humidity environments. Enhancing the hygroscopic properties of protein-based fish adhesives has the potential to unlock new opportunities and applications, providing a healthier and more environmentally sustainable alternative to petroleum-based adhesives. [ABSTRACT FROM AUTHOR]

Soil stabilization using polymers and fibers has been widely investigated in recent years. This study introduces an innovative approach by integrating synthetic polymer (AH polymer) with natural fibers (sisal fiber) for sand stabilization. A comprehensive experimental framework was established to assess the impact of varying polymer content (1%, 2%, 3%, and 4%) and fiber content (0.2%, 0.4%, 0.6%, and 0.8%, by the mass of dry sand), and densities, on the mechanical properties of stabilized sand, including compressive strength (UCS), tensile strength (TS), and flexural strength (FS). The synergistic stabilization effects of the polymer and fibers were elucidated through SEM. The findings indicate that the synergistic application of AH polymer and sisal fibers significantly enhances the structural integrity of sand. Notably, the UCS, TS, and FS exhibited a well-linear relationship with both the polymer and fiber content. The strengthening effect of fiber was particularly pronounced in samples with higher polymer content. According to the strength increase rate, the optimal polymer content is 2%, and optimal fiber content is 0.6% for the UCS, 0.4% for the TS and 0.8% for the FS. An increase in density was observed to linearly augment the UCS and FS. For sand with 2% polymer and 0.8% fiber, the TS increased linearly with the increment in density, however, for sand with 4% polymer and 0.4% fiber, TS kept a non-monotonic relationship with density. The study also revealed that augmenting the content of polymer and fibers diminishes the brittleness of the stabilized sand, whereas an increase in density has the opposite effect. Furthermore, the incorporation of polymer and fibers resulted in an elevated deformation modulus. The polymer functions as an adhesive, binding fibers to sand particles, while the fibers create a network-like structure that amplifies the effective contact area among sand particles, thereby substantially improving the mechanical properties of the sand. [ABSTRACT FROM AUTHOR]

Protein-based fish adhesives have historically been used in various bonding applications; however, due to the protein’s high affinity for water absorption, these adhesives become destabilized in high-moisture environments, resulting in reduced bondline strength and early failure. This limitation makes them unsuitable for industrial applications with higher demands. To address this issue, water-insoluble raw powder materials such as iron, copper, or zeolite were incorporated into natural fish adhesives. In this study, the hygroscopicity, dry matter content, thermal analysis (TGA/DSC), FT-IR spectroscopy, surface tension measurements, vapour permeability, and scanning electron microscope (SEM) of the modified adhesives were determined. In addition, the bonding properties of the modified adhesives were evaluated by the tensile shear strength of the lap joints, and mould growth was visually inspected. The resulting modified protein-based adhesives demonstrated improved stability in high humidity environments. Enhancing the hygroscopic properties of protein-based fish adhesives has the potential to unlock new opportunities and applications, providing a healthier and more environmentally sustainable alternative to petroleum-based adhesives.

Polymer-stabilized liquid crystals (PSLCs) are multi-functional materials consisting of polymer networks in a continuous phase of liquid crystals (LCs), of which polymer networks provide anchoring energy to align the LCs. A number of improvements are detailed, including polymer-stabilized nematic liquid crystals (PSNLCs), polymer-stabilized cholesteric liquid crystals (PSCLCs), polymer-stabilized blue phase liquid crystals (PSBPLCs), polymer-stabilized smectic liquid crystals (PSSLCs), polymer-stabilized ferroelectric liquid crystals (PSFLCs), and polymer-stabilized antiferroelectric liquid crystals (PSAFLCs) in this review. Polymer stabilization has achieved multiple functionalities for LCs; in smart windows, a sufficiently strong electric field allows the LCs to reorient and enables switching from a scattering (transparent) state to a transparent (scattering) state. For broadband reflectors, the reflection bandwidth of LCs is manually tuned by electric fields, light, magnetic fields, or temperature. PSBPLCs open a new way for next-generation displays, spatial light modulators, sensors, lasers, lenses, and photonics applications. Polymer networks in PSFLCs or PSAFLCs enhance their grayscale memories utilized in flexible displays and energy-saving smart cards. At the end, the remaining challenges and research opportunities of PSLCs are discussed. [ABSTRACT FROM AUTHOR]

Cholesteric liquid crystals (CLC) are molecules that can self-assemble into helicoidal superstructures exhibiting circularly polarized reflection. The facile self-assembly and resulting optical properties makes CLCs a promising technology for an array of industrial applications, including reflective displays, tunable mirror-less lasers, optical storage, tunable color filters, and smart windows. The helicoidal structure of CLC can be stabilized via in situ photopolymerization of liquid crystal monomers in a CLC mixture, resulting in polymer-stabilized CLCs (PSCLCs). PSCLCs exhibit a dynamic optical response that can be induced by external stimuli, including electric fields, heat, and light. In this review, we discuss the electro-optic response and potential mechanism of PSCLCs reported over the past decade. Multiple electro-optic responses in PSCLCs with negative or positive dielectric anisotropy have been identified, including bandwidth broadening, red and blue tuning, and switching the reflection notch when an electric field is applied. The reconfigurable optical response of PSCLCs with positive dielectric anisotropy is also discussed. That is, red tuning (or broadening) by applying a DC field and switching by applying an AC field were both observed for the first time in a PSCLC sample. Finally, we discuss the potential mechanism for the dynamic response in PSCLCs. [ABSTRACT FROM AUTHOR]

Recently, there has been considerable research on optical devices, such as liquid crystal (LC) lenses and special optical plates, using LCs. In such devices, relatively small LC cells are frequently used, or unique LC orientations are required. As an LC orientation process, we focused on the LC director's orientation induced by the magnetic force line distribution of a small neodymium magnet. We propose a simple method for obtaining radial orientation, which is rather difficult to obtain using the ordinary rubbing method. The initial orientation in the LC cell is a vertical orientation cell with almost zero azimuth anchoring. With the proposed method, the reorientation process is performed with an assisting electric field and a small permanent magnet, unlike the conventional magnetic field orientation process that requires a large electromagnet. Furthermore, a polymer stabilization treatment is used to fix the obtained radial orientation pattern in the LC cell. After the treatment, the applying voltage can control the tilt angle of the director in weak polymer treatment, and a completely fixed orientation pattern can be obtained that in strong. [ABSTRACT FROM AUTHOR]

Ag nanoclusters of 5 atoms, Ag 5 , synthesized by a kinetic control method, show exceptional catalytic activities for the redox elimination of radicals. Their use as catalytic radical scavengers in industrially relevant processes involving detrimental free radical formation, such as polymer stabilization, is here demonstrated, opening a new class of catalytic antiradicals with many potential industrial and/or biomedical applications. [Display omitted] Silver nanoclusters of five atoms (Ag 5) display outstanding catalytic activities for the deactivation of radicals. Using 2,2-diphenyl-1‑picrylhydrazyl (DPPH) radical as a model system, we observed a fast radical reduction to DPPH anions using only [Ag 5 ] 3 to 4 orders of magnitude less than [DPPH]. Moreover, nanoclusters remain stable at the end of the reaction, and can deactivate again DPPH radicals at the same rate, indicating that they act as anti-radical catalysts. The radical scavenger catalytic activity of Ag 5 proceeds selectively through the oxidation of methanol (used to dissolve the radical) to formaldehyde, which is supported by DFT calculations. The obtained catalytic rate constants are almost 2 orders of magnitude higher than oxidases, and more than 4 orders of magnitude larger than graphene quantum dots. We also show that Ag 5 not only catalyze the reduction of radicals but also their oxidation, promoting the inhibition of the autoxidation mechanisms of hydrocarbon polymers, which are very sensitive to the presence of radicals. For this purpose, thin films of two industrially relevant polymers (polyisoprene and acrylonitrile–butadienestyrene copolymer), were exposed to standard simulated photo-ageing conditions in the presence of Ag 5. Using Attenuated Total Reflection-FTIR and DFT modeling we observed that, although Ag 5 nanoclusters, with ≈ 15% surface coverage, do not totally inhibit the oxidation, they favour a decomposition that yields inactive products, in contrast with the more detrimental ketone formation pathway. These results not only open new possibilities for developing a post-process inhibition of polymer degradation, for which nowadays there are no efficient procedures, but also, they could be used as very efficient dual-redox catalytic radical scavengers for different industrial or biomedical purposes. [ABSTRACT FROM AUTHOR]

Liquid crystals (LCs) are key functional materials that are broadly adopted in various fields due to their stimuli‐responsiveness. Recently, LCs with hierarchical architectures have brought new effects to optics and attracted intensive attention. In smectic A phase, the parallel molecular layers are periodically wrapped to form toric focal conic domains (TFCDs) under antagonistic boundary conditions (i.e., hybrid alignment conditions). TFCD shows great potential in nanofabrication and integral imaging. However, the arbitrary tailoring of TFCD is still challenging, and the robustness of hierarchical configuration hinders the tunability. Here, a radial alignment lattice is adopted to guide the local orientation of LCs and thus facilitates predefining the lattice symmetry and domain size of TFCDs. By introducing polymer stabilization and optimizing the composition, the sample simultaneously maintains the director distribution inside smectic layers and possesses the stimuli‐responsiveness of nematic phase at room temperature. By this means, microlens arrays are demonstrated with reversible electrical tunability. The strategy can be extended to other smectic configurations and may upgrade existing dynamic optics. [ABSTRACT FROM AUTHOR]

In this paper, drop‐on‐demand (DoD) printing is demonstrated of polymer stabilized chiral nematic liquid crystal (PSCLC) privacy windows that can function in either a conventional mode (scattering to transparent) or reverse mode (transparent to scattering) with the application of an electric field. Inkjet printed droplets of the PSCLC mixture, with diameters of the order of 100–200 µm and sandwiched in LC layer thicknesses of ≈10–15 µm, are characterized in terms of their transmission as a function of the electric field amplitude and the response times for switching into and out of the scattering state. The results show that the printed droplets, and arrays thereof, exhibit similar electro‐optical properties to analogous thin‐film devices, but with the ability to incorporate bespoke features such as images and decorative patterns. Finally, the electro‐optical switching of a printed PSCLC privacy window whereby alphanumeric characters can be made to appear and disappear with the application of an electric field is demonstrated. [ABSTRACT FROM AUTHOR]

• Magnetic nanoparticles can be produced in a membrane reactor with in situ stabilization. • Stabilization is performed using several polymers as PEG, PAA, PVA, PVP, Chitosan, and alginate. • Temperatures and ultrasound play an important role in situ stabilization of nanoparticles in membrane reactors. Membrane reactors have been proven to be effective in producing nanoparticles with reduced polydispersity indices. Recently, our group has incorporated this technology into the synthesis of ferromagnetic nanoparticles. In the initial phase, we conducted post-synthesis stabilization experiments to assess the performance of various polymeric agents. Polyacrylic acid (PAA) was chosen because of its notable affinity for the functional groups on the nanoparticle surface. Subsequently, in situ stabilization experiments were conducted using a membrane reactor, with variations in PAA addition flow rates ranging from 0.33 to 1.5 mL/min and maturation times in an ultrasonic bath ranging from 0.5 to 2 h. The samples were characterized in terms of their hydrodynamic diameter, polydispersity, and Z-potential. Notably, the smallest particle size was achieved at the intermediate point with a PAA flow rate of 0.66 mL/min. However, the influence of maturation time did not follow a predictable pattern; the most favorable characteristics, based on the analyzed variables, were observed at 1.5 and 2 h. [ABSTRACT FROM AUTHOR]

Polymer-stabilized liquid crystals (PSLCs) are multi-functional materials consisting of polymer networks in a continuous phase of liquid crystals (LCs), of which polymer networks provide anchoring energy to align the LCs. A number of improvements are detailed, including polymer-stabilized nematic liquid crystals (PSNLCs), polymer-stabilized cholesteric liquid crystals (PSCLCs), polymer-stabilized blue phase liquid crystals (PSBPLCs), polymer-stabilized smectic liquid crystals (PSSLCs), polymer-stabilized ferroelectric liquid crystals (PSFLCs), and polymer-stabilized antiferroelectric liquid crystals (PSAFLCs) in this review. Polymer stabilization has achieved multiple functionalities for LCs; in smart windows, a sufficiently strong electric field allows the LCs to reorient and enables switching from a scattering (transparent) state to a transparent (scattering) state. For broadband reflectors, the reflection bandwidth of LCs is manually tuned by electric fields, light, magnetic fields, or temperature. PSBPLCs open a new way for next-generation displays, spatial light modulators, sensors, lasers, lenses, and photonics applications. Polymer networks in PSFLCs or PSAFLCs enhance their grayscale memories utilized in flexible displays and energy-saving smart cards. At the end, the remaining challenges and research opportunities of PSLCs are discussed.

Sufficient boron-10 isotope (10B) accumulation by tumor cells is one of the main requirements for successful boron neutron capture therapy (BNCT). The inability of the clinically registered 10B-containing borophenylalanine (BPA) to maintain a high boron tumor concentration during neutron irradiation after a single injection has been partially solved by its continuous infusion; however, its lack of persistence has driven the development of new compounds that overcome the imperfections of BPA. We propose using elemental boron nanoparticles (eBNPs) synthesized by cascade ultrasonic dispersion and destruction of elemental boron microparticles and stabilized with hydroxyethylcellulose (HEC) as a core component of a novel boron drug for BNCT. These HEC particles are stable in aqueous media and show no apparent influence on U251, U87, and T98G human glioma cell proliferation without neutron beam irradiation. In BNCT experiments, cells incubated with eBNPs or BPA at an equivalent concentration of 40 µg 10B/mL for 24 h or control cells without boron were irradiated at an accelerator-based neutron source with a total fluence of thermal and epithermal neutrons of 2.685, 5.370, or 8.055 × 1012/cm2. The eBNPs significantly reduced colony-forming capacity in all studied cells during BNCT compared to BPA, verified by cell-survival curves fit to the linear-quadratic model and calculated radiobiological parameters, though the effect of both compounds differed depending on the cell line. The results of our study warrant further tumor targeting-oriented modifications of synthesized nanoparticles and subsequent in vivo BNCT experiments. [ABSTRACT FROM AUTHOR]

Cholesteric liquid crystals (CLC) are molecules that can self-assemble into helicoidal superstructures exhibiting circularly polarized reflection. The facile self-assembly and resulting optical properties makes CLCs a promising technology for an array of industrial applications, including reflective displays, tunable mirror-less lasers, optical storage, tunable color filters, and smart windows. The helicoidal structure of CLC can be stabilized via in situ photopolymerization of liquid crystal monomers in a CLC mixture, resulting in polymer-stabilized CLCs (PSCLCs). PSCLCs exhibit a dynamic optical response that can be induced by external stimuli, including electric fields, heat, and light. In this review, we discuss the electro-optic response and potential mechanism of PSCLCs reported over the past decade. Multiple electro-optic responses in PSCLCs with negative or positive dielectric anisotropy have been identified, including bandwidth broadening, red and blue tuning, and switching the reflection notch when an electric field is applied. The reconfigurable optical response of PSCLCs with positive dielectric anisotropy is also discussed. That is, red tuning (or broadening) by applying a DC field and switching by applying an AC field were both observed for the first time in a PSCLC sample. Finally, we discuss the potential mechanism for the dynamic response in PSCLCs.

The dynamic electro‐optic (EO) response of polymer‐stabilized cholesteric liquid crystals prepared using unpolarized UV light (U–PSCLC), such as reflection bandwidth broadening and either red or blue tuning of the reflection peak, has been previously reported. Herein, recent efforts to use a polarized single argon‐ion laser beam to create PSCLCs (L–PSCLCs) with higher‐order reflections are described. The L–PSCLCs exhibit a primary reflection peak in the near‐infrared (NIR) regime and a second‐order reflection band with a narrow bandwidth in the visible regime that results from a deformed in‐plane CLC helical structure. The initial positions of the reflection bands are adjusted by the chiral dopant concentrations of the CLC mixture, and red, green, and blue reflection colors from the second‐order Bragg reflection are demonstrated. The primary and the second‐order reflection bands can be shifted to longer wavelengths by application of a DC electric field. The reflection efficiency of the higher‐order reflection notch increases with polymer concentration, which affects the degree of in‐plane deformation and fixation of the CLC helix. Modeling is used to further explain the formation of the higher‐order reflection bands of PSCLCs observed experimentally.

This research aims to study the use of cationic (polyvinyl acetate, PVA) and anionic (polyacrylamide, PAM) polymers on the improvement of strength and swell behaviour of expansive soils. All the prepared samples were tested and results were analysed to visualize the effectiveness of admixtures. The use of both polymers showed improvement in the unconfined compressive strength of expansive soil. One dimensional oedometric swell tests were conducted for the optimum content of polymer producing the highest UCS value and one another proportion of polymer to investigate the swell potential and swelling pressure of polymer treated soil. The changes in the microstructure of the treated soil were analysed through SEM imaging. [ABSTRACT FROM AUTHOR]

Sufficient boron-10 isotope (10B) accumulation by tumor cells is one of the main requirements for successful boron neutron capture therapy (BNCT). The inability of the clinically registered 10B-containing borophenylalanine (BPA) to maintain a high boron tumor concentration during neutron irradiation after a single injection has been partially solved by its continuous infusion; however, its lack of persistence has driven the development of new compounds that overcome the imperfections of BPA. We propose using elemental boron nanoparticles (eBNPs) synthesized by cascade ultrasonic dispersion and destruction of elemental boron microparticles and stabilized with hydroxyethylcellulose (HEC) as a core component of a novel boron drug for BNCT. These HEC particles are stable in aqueous media and show no apparent influence on U251, U87, and T98G human glioma cell proliferation without neutron beam irradiation. In BNCT experiments, cells incubated with eBNPs or BPA at an equivalent concentration of 40 µg 10B/mL for 24 h or control cells without boron were irradiated at an accelerator-based neutron source with a total fluence of thermal and epithermal neutrons of 2.685, 5.370, or 8.055 × 1012/cm2. The eBNPs significantly reduced colony-forming capacity in all studied cells during BNCT compared to BPA, verified by cell-survival curves fit to the linear-quadratic model and calculated radiobiological parameters, though the effect of both compounds differed depending on the cell line. The results of our study warrant further tumor targeting-oriented modifications of synthesized nanoparticles and subsequent in vivo BNCT experiments.

The behavior of two newly formulated bi-component orthoconic antiferroelectric liquid crystalline (OAFLC) systems, i.e., the Compound A + Compound B mixture system and Compound C + Compound B mixture system has been discussed in light of temperature and concentration dependencies of helical pitch length, spontaneous polarization, relaxation time, bulk viscosity, and the anchoring energy strength coefficient, together with static dielectric permittivity (ε) and dielectric anisotropy. Compound A + Compound B mixtures possess spontaneous polarization between 190–340 nC.cm−2 and fast relaxation times between 190–320 µs in the smectic antiferroelectric SmCA* phase at room temperature. Compound C + Compound B mixtures also have a spontaneous polarization in the range of 190–280 nC.cm−2 and relaxation times in the range of 190–230 µs at room temperature. Most of the mixtures have a helical pitch below one micrometer in the SmCA* phase. These advanced mixtures show a broad temperature range of the antiferroelectric SmCA* phase, fast switching of molecules under an applied electric field, negative dielectric anisotropy and a short helical pitch, confirming the advantage of designing new polymer-stabilized OAFLC that is targeted for novel application in sensing devices, utilizing the fast responsive electro-optical modulation elements.

Electrical reconfiguration of the cholesteric liquid crystal phase is subject to extensive prior research. Here, a distinctive composition that allows the typically singular selective reflection to be split into two distinct and tunable selective reflections with an electric field is reported. The distinctive electro‐optic phenomena (reflection notch splitting) are shown to be composition dependent and enabled by the introduction of appreciable amounts of side chain liquid crystalline mesogens. Functional opportunities enabled by the distinguished control of the two reflection elements are demonstrated, including spectrally variant polarization filters. [ABSTRACT FROM AUTHOR]

Blue phase liquid crystals (BPLCs) composed of double-twisted cholesteric helices are promising materials for use in next-generation displays, optical components, and photonics applications. However, BPLCs are only observed in a narrow temperature range of 0.5–3 °C and must be stabilized with a polymer network. Here, we report on controlling the phase behavior of BPLCs by varying the concentration of an amorphous crosslinker (pentaerythritol triacrylate (PETA)). LC mixtures without amorphous crosslinker display narrow phase transition temperatures from isotropic to the blue phase-II (BP-II), blue phase-I (BP-I), and cholesteric phases, but the addition of PETA stabilizes the BP-I phase. A PETA content above 3 wt% prevents the formation of the simple cubic BP-II phase and induces a direct transition from the isotropic to the BP-I phase. PETA widens the temperature window of BP-I from ~6.8 °C for BPLC without PETA to ~15 °C for BPLC with 4 wt% PETA. The BPLCs with 3 and 4 wt% PETA are stabilized using polymer networks via in situ photopolymerization. Polymer-stabilized BPLC with 3 wt% PETA showed switching between reflective to transparent states with response times of 400–500 μs when an AC field was applied, whereas the application of a DC field induced a large color change from green to red.

Stabilized reverse twisted nematic liquid crystal devices (RTN-LCDs) were fabricated using formation of a polymer matrix under UV irradiation with an applied voltage (sustain voltage) in the vicinity of the alignment layers. In the absence of an applied voltage, the non-stabilized RTN structure gradually returns to a splay twist structure. The sustain voltage was decreased with an increase in temperature. A stabilized long-pitch supertwisted nematic (LPSTN) structure could also be formed during the RTN structure stabilization process with a much lower sustain voltage at a temperature near the clearing point. The chiral pitch for the LPSTN structure is longer than that for a typical STN structure. LPSTN-LCDs similar to RTN-LCDs show a large reduction in both the threshold and saturation voltage compared with those for TN-LCDs consisted of the same LC materials. Furthermore, a notable feature of LPSTN-LCDs is a change to a TN structure when a high voltage is applied. A black state can be realized due to the change from the LPSTN structure to the RTN structure unlike the typical STN mode under the crossed nicols condition. In contrast STN-LCDs retain their color due to the retardation because the RTN and LPSTN states are considered topologically equivalent.

When a LCD display static images, power consumption can be reduced by employing a low driving frequency. However, when the driving frequency is decreased, there is a problem that the brightness of the display may change with time, a phenomenon known as flickering. One factor responsible for the flickering issue is flexoelectric effect. We show that flickering in ADvanced Super Dimension Switch (ADS) LCD can be significantly reduced by doping a liquid crystal dimer and using polymer stabilization. We demonstrated that 2 Hz driving frequency can be used to display static images. [ABSTRACT FROM AUTHOR]

Power consumption of a liquid crystal display, when it is used to display static images, can be reduced by using low frequency driving. However, when the driving frequency is decreased, the brightness of the display may change with time, a phenomenon known as image flickering. One factor responsible for the flickering issue is flexoelectric effect which is sensitive to the polarity of the applied voltage. We show that the flickering in fringe field switching (FFS) LCD can be significantly reduced by doping a liquid crystal dimer and using polymer stabilization. We demonstrated that 2 Hz driving frequency can be used to display static images. [ABSTRACT FROM AUTHOR]

It has previously been shown that for polymer-stabilized cholesteric liquid crystals (PSCLCs) with negative dielectric anisotropy, the position and bandwidth of the selective reflection notch can be controlled by a direct-current (DC) electric field. The field-induced deformation of the polymer network that stabilizes the devices is mediated by ionic charges trapped in or near the polymer. A unique and reversible electro-optic response is reported here for relatively thin films (≤5 μm). Increasing the DC field strength redshifts the reflection notch to longer wavelength until the reflection disappears at high DC fields. The extent of the tuning range is dependent on the cell thickness. The transition from the reflective to the clear state is due to the electrically controlled, chirped pitch across the small cell gap and not to the field-induced reorientation of the liquid crystal molecules themselves. The transition is reversible. By adjusting the DC field strength, various reflection wavelengths can be addressed from either a different reflective (colored) state at 0 V or a transparent state at a high DC field. Relatively fast responses (~50 ms rise times and ~200 ms fall times) are observed for these thin PSCLCs.

In this study, we synthesized two novel monofunctional acrylate monomers A0DA and A3DA featuring a benzene core and a dodecyl tail, and then investigated their effect on blue phase liquid crystal (BPLC) stabilization. The benzene core is directly linked to the acrylate unit in A0DA, which forms a rigid polymeric backbone. Whereas in A3DA,a propyl spacer is employed to separate the benzene unit from the acrylate group, thereby allowing backbone mobility. By using A0DA as a monofunctional monomer in the BPLC precursor composite, stabilization of BPLC was not seen upon photopolymerization. Interestingly, the use of A3DA showed successful stabilization of BPI lattice structure after polymerization. These results confirm that the origin of stabilization effect of blue phase is the flexibility of A3DA backbone employed; therefore, the polymeric backbone flexibility is suggested to have a major influence on BP stabilization process. Furthermore, we demonstrated a low voltage electro-optical switching of PS-BPLC built on A3DA, while preserving other desirable properties of BPLC. The present study provides useful insight into monomer designs towards BPLC stabilization and enhancement of electro-optical performance. [ABSTRACT FROM AUTHOR]

New stabilization method for in situ self-assembled homeotropic alignment layer was proposed. The benzoic acid derivative and mesogenic diacrylate were employed as in situ alignment agent and reactive monomer (RM), respectively. This alignment layer offers stable vertical alignment (VA) of liquid crystals (LCs) via photopolymerization of RM. The formation process of the stabilized alignment layer is very simple and involves doping of the VA agent and RM. The fabricated LC cell exhibited low residual direct current and stable VA properties during long term operation. Our definitive alignment method is useful in fabricating LC devices requiring high reliability. [ABSTRACT FROM PUBLISHER]

This article illustrates the application of using polymer stabilization in creating a new nanocomposite material with clay soil. Various tests with different polymer contents were performed to study the effect of using polypropylene as a stabilizing agent on both microstructure and geotechnical clay properties. These experiments showed that the resulting nanocomposites acted as nanofiller materials which decreased the plasticity and compressibility parameters of the treated clay. The initial structural analysis helped in a better understanding of the modified microstructure and the measured size of induced nanocomposites. The constructed inclusions filled the inter-assembling pores thus notably producing a higher vertical effective yield stress which again reduced the volumetric shrinkage and created isotropic and compressible materials with a lesser extent of desiccation cracks. It also increased the tensile and the shear strength of the stabilized clay with an increase in the nanocomposites size. This technique can be effectively used for road embankments and slope stabilization.

Hindered amine light stabilizers are essential for the stabilization of synthetic polymers, particularly for materials used for outdoor applications. Although up to now a considerable number of studies dealing with the analytics of this class of stabilizers had been published, especially the determination of oligomeric hindered amine light stabilizers is still an analytical challenge. In the current work, a fast and simple liquid chromatographic method for the quantitative determination of oligomeric hindered amine light stabilizers is presented. A key aspect of this method is their completely different retention behavior depending on the pH, enabling a single peak elution approach by a pH gradient run. This allows a quantitation with simple UV detection independent of the actual oligomeric composition. Calibration curves within the concentration range relevant for the analysis of real polymer samples (LOQ = 70 mg/L) were constructed with R2 values above 0.99. Spiked extracts from polyolefin samples showed recovery rates between 97.3 and 102.9% for five different commercial hindered amine light stabilizers. Relative standard deviations were between 2.0 and 3.9%. Furthermore, it was demonstrated that the employed approach can be easily adapted for mass spectrometry detection. [ABSTRACT FROM AUTHOR]

We proposed a novel reserve optical compensated bend (ROCB) liquid crystal display mode. This mode has advantages of a rapid response time and self-compensation for large viewing angle. We also used polymer network to stabilize the bend configuration. We achieved ultra-fast response time of sub-millisecond, which is suitable for color sequential operation. [ABSTRACT FROM AUTHOR]

The cobalt and copper nanoparticles were prepared by reduction of metals using the 2-propanol at presence of chitosan Bombyx mori. The structural measurements show that the chitosan molecules prevent the agglomeration and oxidation of metal particles. It was established that chitosan is a nano-reactor and its concentration influences on the size and distribution of NP in a polymeric matrix. [ABSTRACT FROM AUTHOR]

The blue phase liquid crystal (BPLC) is a highly ordered liquid crystal (LC) phase found very close to the LC–isotropic transition. The BPLC has demonstrated potential in next-generation display and photonic technology due to its exceptional properties such as sub-millisecond response time and wide viewing angle. However, BPLC is stable in a very small temperature range (0.5–1 °C) and its driving voltage is very high (∼100 V). To overcome these challenges recent research has focused on solutions which incorporate polymers or nanoparticles into the blue phase to widen the temperature range from around few °C to potentially more than 60 °C. In order to reduce the driving voltage, strategies have been attempted by modifying the device structure by introducing protrusion or corrugated electrodes and vertical field switching mechanism has been proposed. In this paper the effectiveness of the proposed solution will be discussed, in order to assess the potential of BPLC in display technology and beyond.

Hindered amine light stabilizers are an important class of stabilizers that protect synthetic polymers from degradation and thus from changing mechanical and optical properties. The current study presents an HPLC method capable of separating oligomeric hindered amine light stabilizers on a commercially available stationary phase, employing an MS-compatible novel mobile phase. Based on the exact masses observed with Q-TOF-MS, a comprehensive characterization of five different types of oligomeric hindered amine light stabilizers was achieved, leading to structural information not included in the datasheets provided by the suppliers. For the different investigated hindered amine light stabilizers, a number of recurring units up to 17 and a molecular weight of 5200 g/mol were detected. Furthermore, the analysis of stabilizer extracts of processed polypropylene samples containing different types of hindered amine light stabilizers revealed significant differences in the oligomeric pattern between standards and polymer samples. Thus, changes in the analytes' oligomeric pattern resulting from processing or aging of polymer materials can be monitored with the presented method. [ABSTRACT FROM AUTHOR]

While liquid phase exfoliation can be used to produce nanosheets stabilized in polymer solutions, very little is known about the resultant nanosheet size, thickness, or monolayer content. The present study uses semiquantitative spectroscopic metrics based on extinction, Raman, and photoluminescence (PL) spectroscopy to investigate these parameters for WS2 nanosheets exfoliated in aqueous poly(vinyl alcohol) (PVA) solutions. By measuring Raman and PL simultaneously, the monolayer content can be tracked via the PL/Raman intensity ratio while varying processing conditions. The PL is found to be maximized for a stabilizing polymer concentration of 2 g L−1. In addition, the monolayer content can be controlled via the centrifugation conditions, exceeding 5% by mass in some cases. These techniques have allowed tracking the ratio of PL/Raman in a droplet of polymer-stabilized WS2 nanosheets as the water evaporates during composite formation. No evidence of nanosheet aggregation is found under these conditions although the PL becomes dominated by trion emission as drying proceeds and the balance of doping from PVA/water changes. Finally, bulk PVA/WS2 composites are produced by freeze drying where >50% of the monolayers remain unaggregated, even at WS2 volume fractions as high as 10%. [ABSTRACT FROM AUTHOR]

We demonstrated that polymer stabilization can significantly improve the response time of in-plane-switching liquid crystal display. We carried out a systematic study of the effect of polymer networks on the performance of in-plane-switching liquid crystal display. The polymer network has a strong aligning effect on the liquid crystal and has the advantage of reducing the switching time of the display but may have the disadvantage of ruining the contrast ratio because of its scattering effect. Through optimization, we successfully improve the switching time (less than 6 ms) and reduce the scattering and thus retain high contrast ratio (higher than 1000:1). [ABSTRACT FROM AUTHOR]

We developed a switchable diffuser for transparent liquid crystal displays. The diffuser is based on polymer stabilized cholesteric texture (PSCT) light shutter. It can be switched between a transparent state and a milky scattering state by applying voltages. The transmittance of the transparent state is near 90%. The reflectance of the scattering state is higher than 30%. We also developed a transparent ADS display with the PSCT, which has excellent viewing angle. [ABSTRACT FROM AUTHOR]

Polymer-stabilized V-mode Ferroelectric Liquid Crystals (PSV-FLCs) are attractive for a next generation of LC display. However, in the rubbing technique which is conventionally used for LC molecular alignment, the rubbing scratches form on the alignment film surface, and then, the rubbing scratch pattern is clearly observed in the texture of FLC. Therefore, the high contrast ratio cannot be obtained due to the optical leakage. In this research, we introduce the photo-alignment technique to PSV-FLC. As a result, the optical leakage can be largely suppressed by the photo-alignment technique, and thus, the photo-alignment technique is effective to PSV-FLCs. [ABSTRACT FROM AUTHOR]

The temperature range of blue phase liquid crystal can be extended through the use of polymer stabilization. In this work, the mixing condition for the host liquid crystal mixture containing E8, PE-5CNF, and CPP-3FF; and the monomer UCL-011 and the chiral dopant NYC-22133L was investigated. Typically, the operating temperature for displays should be in the range of −40 to +80°C. The chiral dopant and monomer tend to lower the clearing temperature; thus, the host LC should have a high BP-Iso clearing temperature. In this work, optimization of the ratio of the host liquid crystal with respect to the monomer was carried out. It was found that a ratio of 5:3:2 for E8: PE-5CNF: CPP-3FF gave a polymer stabilized blue phase of ∼50.4°C. Driving voltage and electro-optic hysteresis was also investigated, yields a conclusion that a trade-off between driving voltage and hysteresis exists for the PSBPLC mixture that was investigated. [ABSTRACT FROM PUBLISHER]

This research was focused on the efficiency of transition metal ions (TMI) as hydroxyl radical scavengers in conditions that mimic the fuel cell operating environment. The stabilized hydrocarbon proton conductive polymer membranes (PEMs) were obtained via sulfopropylation of poly(vinyl alcohol-co-ethylene) with ethylene content of 44 mol % (PEVA) followed by cross-linking of polymer chains with glutar aldehyde. Synthetized membranes were characterized by FTIR, elementary and thermogravimetric analysis. Examination of synthetized membranes morphology was performed with SEM and AFM techniques. The protons of sulfonic groups were substituted by transition metal ions Ce(III), and Mn(II) with the neutralization varying from 2.5 up to 10 mol %. The results of EPR measurements provided evidence of scavenging of HO radicals by Ce(III) and Mn(II), leading to a weakening of their attack on the polymer. The lowering of carbon centered radicals concentration led to slower polymer degradation thus the presence of the cerium (III) and manganese (II) ions is expected to extend the membrane lifetime in FC operation conditions. [ABSTRACT FROM AUTHOR]

Liquid crystals (LCs) are attractive for optical devices, such as lenses because of their large birefringence and high response to external field. However, the low-speed response of nematic LCs often becomes an obstacle to the progress of LC devices. In this study, we research the lens effect of ferroelectric LC by using a voltage-gradient cell. As a result, it is found that in order to obtain the lens effect in FLC, the wide cell gap, the large tilt angle and/or the large birefringence of FLC materials are necessary to increase the birefringence variation under the gradient voltage in addition to the monostabilization of FLC media. [ABSTRACT FROM PUBLISHER]

In this research, we focus on the polymer-stabilized V-mode FLC (PSV-FLC) in which a doped monomer is photocured in the SmA phase. PSV-FLC may show monostable and V-shaped electrooptical characteristics with a grayscale capability. In this paper, we investigate the dependence of the monostable capability on the fabricating conditions such as monomer materials, polymer concentration, and UV energy. Furthermore, in order to increase the contrast ratio, we introduce a photo-alignment technique. As a result, it is found that the monostable capability of PSV-FLC strongly depends on their conditions. Furthermore, the more uniform molecular alignment without rubbing scratch pattern was obtained by using the photo-alignment film. [ABSTRACT FROM PUBLISHER]

Polymer stabilization is an attractive technique because the physical property of liquid crystals can be improved and furthermore the new characteristics may occur. In this study, we try to obtain a high-speed response of nematic liquid crystals by using polymer stabilization technique for realization of the field sequential color. We have researched the dependence of the electrooptical characteristics such as response time and threshold voltage on UV irradiation energy, polymer and liquid crystal materials, and polymer concentration. As a result, it is found that the electrooptical characteristics strongly depend on their conditions. [ABSTRACT FROM PUBLISHER]

A new method of improving the response time of vertical alignment (VA) liquid crystal devices using surface polymer stabilization is introduced. A minute amount of a reactive monomer and photo-initiator is mixed with a nematic liquid crystal host and the mixture is polymerized under UV light to form sub-micron sized polymer protrusions on the two substrates of the cell with an applied bias voltage. Several kinds of reactive monomers with different molecular structures are tested, and a faster response time and a lower light leakage at dark state are achieved. This finding will be useful for display applications. [ABSTRACT FROM PUBLISHER]

Highlights: [•] mPEG-PEI copolymers were prepared, the interaction mechanisms with SiNP were studied. [•] Electrostatic attractions govern the adsorption process of mPEGlowPEI copolymer. [•] Hydrogen bonding takes part in the adsorption process of mPEGhighPEI copolymer. [•] Increased PEG grafting density does not prevent serum protein adsorption. [•] Inverse dependence of PEG grafting density was observed under biological conditions. [ABSTRACT FROM AUTHOR]