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A simple and facile stereolithography 3D printing technique was utilized to fabricate piezoelectric photopolymer-based polyvinylidene fluoride (PVDF) blends. Different process variables, such as solvent (N,N-dimethylformamide, DMF) to PVDF ratio and PVDF solution to photopolymer resin (PR) ratio, were engineered to enhance the dispersion of the PVDF into the PR so as to achieve the maximum piezoelectric coupling coefficient. Our results demonstrate that a ratio of 1:10 (PVDF:DMF) and 2 wt%-PVDF/PR was optimal for the best dissolution of the PVDF, 3D printability, and piezoelectric properties. Under these conditions, the blend generated ±0.121 nA under 80 N dynamic loading excitation. We believe that the findings of this work would promote many further studies on the mass production of flexible piezoelectric polymer blends with higher quality finished surface and design flexibility.

A series of novel absorbents based on Cu-BDC MOFs decorated over graphene oxide (GrO) and carbon nanotubes (CNTs) hybrid nanocomposites, namely Cu-BDC@GrO and Cu-BDC@CNT, are synthesized via a facile and one-pot green solvothermal method for water remediation. The nanocomposites were characterized by XRD, TEM, SEM, EDS, Raman, FTIR, TGA, XPS, Zetasizer and ICP-OES instruments. XRD results confirmed the high crystalline structure of the synthesized hybrid nanocomposites. Morphological analysis by SEM and TEM verified the successful decoration of nano-sized Cu-BDC MOFs over GrO and CNT platforms; whereas, EDS and XPS analysis confirmed the presence of all components in the hybrid nanocomposites. Bisphenol A was used in this study as a model organic pollutant that is sometimes present in the industrial wastewater to test the adsorption capacity of the prepared hybrid nanomaterials toward their removal from water. The hybrid nanomaterials showed remarkable adsorption capacity of 182.2 and 164.1 mg/g toward the removal of BPA, which was several times higher than that of 60.2 mg/g for Cu-BDC MOF itself. The Langmuir, Freundlich, Temkin and D-R isotherm models were applied to analyze the experimental data and the results revealed that the Freundlich model describes the experimental data best. A kinetic study was carried out and it showed that the prepared nanomaterials could remove maximum amount of BPA from water in 30 min. The pseudo-first order, pseudo-second order and intra-particle diffusion models were applied to evaluate the kinetic data and the results suggested that the kinetics data could be well fitted to the pseudo-second order kinetic model. Additionally, the BAP adsorption process onto the hybrid nanocomposites was spontaneous and exothermic. The π-π interactions between the BPA and hybrid nanomaterials played a vital role during the BPA adsorption process. The higher adsorption capacity and water stability makes them a good candidate for water remediation applications.

Purpose Shape memory polymer (SMP) is capable of recovering its original shape from a high degree of deformation by applying an external stimulus such as thermal energy. This research presents an integration of two commercial SMP materials (DiAPLEX and Tecoflex) and a material extrusion (ME) printer to fabricate SMP parts and specimens. The material properties such as Young’s modulus of the specimens was examined as a process output. Furthermore, stress-strain curve, strain recovery, instant shape-fixity ratio, long-term shape-fixity ratio and recovery ratio of SMP specimens during a thermo-mechanical cycle were investigated. Design/methodology/approach The ME fabrication settings for the SMP specimens were defined by implementing a design of experiments with temperature, velocity and layer height as process variables. Findings It was found, according to main effect and iteration plots, that fabrication parameters have an impact on Young’s modulus and exist minimum iteration among variables. In addition, Young’s modulus variation of DiAPLEX and Tecoflex specimens was mostly caused by velocity and layer height parameters, respectively. Moreover, results showed that SMP specimens were able to recover high levels of deformation. Originality/value This paper is a reference for process control and for rheological properties of SMP parts produced by ME fabrication process.

Purpose Shape memory polymers (SMPs) are classified as smart materials owing to their inherent stimulus-induced response. SMPs are capable of recovering partially or totally to its original shape after a high degree of deformation by external stimulus. The most used stimuli are thermal, light, magnetic field and electricity. This research aims to characterize the toughness property of thermo-responsive SMP specimens fabricated by the material extrusion (ME) process and to investigate the impact of ME parameters on specimen maximum load and load-displacement curves. Moreover, to investigate the recovery efficiency based on the initial and post toughness generated by the compact tension test. Design/methodology/approach A design of experiments with three parameters (temperature, velocity and layer height) defined the ME settings to fabricate the specimens. The ME raster orientation factor was also evaluated separately. In addition, one more specimen group assisted by a clamp during the recovery process was compared with a specimen control group. After fabrication, specimens were submitted to a thermo-mechanical cycle that encompasses a compact tension test and a thermo-recovery process. Comparison studies of load-displacement, toughness and recovery efficiency of the specimens were carried out to determine the optimized fabrication parameters. Findings It was found that ME parameters and raster orientation impacted the test results. Samples with the clamp support during recovery returned a higher toughness than samples without support. Finally, results showed that the shape memory effect can contribute with up to 43 per cent recovery efficiency in a first recovery and up to 23 per cent in a second recovery of damaged specimens. Originality/value This paper is a reference for toughness and recovery properties of SMP parts produced by the ME fabrication process.

We have reported sucrose-mediated facile route for the preparation of high surface area cobalt (Co), nickel (Ni), and copper (Cu) sponges. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed the sponge-like and nanoparticle-like morphologies of the metal sponges. The catalytic activity of the metal sponges was studied via the reduction of organic pollutants, including 4-nitrophenol (4-NP), methyl orange (MO) and methylene blue (MB) in water. It was found that the Cu sponge exhibited the fastest rate for the reduction of 4-NP, MO, and MB, followed by the Co and Ni sponges, respectively. The metal sponges exhibited excellent catalytic stability for the reduction of 4-NP for multiple cycles. In addition, due to their magnetic properties, the Co and Ni sponges could be easily recovered and reused by applying an external magnetic field.

The current study reports synthesis and characterization of an ecofriendly, cheap and efficient biosorbent, sulfonated spent coffee waste (SCW-SO3H) for water remediation. SCW-SO3H was synthesized through introducing sulfonic acid polar functionalities over the polymeric biomass (cellulose and lignin) of the spent coffee waste (SCW) by a simple, facile and versatile method. ICP-OES, SEM-EDX, FT-IR, XPS, TGA, Raman and UV–vis spectroscopy were used to analyze the developed SCW-SO3H biosorbent and its adsorption capacity towards the removal of different environmental pollutants. In order to optimize and maximize adsorption capacity of the developed biosorbent, different variables such as initial concentration, biosorbent dosage, pH, time and temperature were evaluated. The chemically engineered biosorbent showed excellent pollutant removal capacity of 812 mg/g, 462 mg/g and 302 mg/g toward methylene blue, tetracycline and Cr (VI), respectively. Isotherms studies showed that while organic pollutants adsorption follow Langmuir isotherm, Cr(VI) adsorption follows Freundlich isotherm. It was also found that adsorption of all the adsorbates follow pseudo-second order rate kinetic and thermodynamic values, ΔH >0 and ΔG

This research studied multifunctional sensing capabilities on nanocomposites composed of poly(vinylidene) fluoride (PVDF), BaTiO3 (BT), and multiwall carbon nanotubes (CNTs) fabricated by fused-deposition modeling 3D printing. To improve the dielectric property within BT/PVDF composites, CNTs have been utilized to promote ultrahigh polarization density and local micro-capacitor among BT and polymer matrix. The 3D printing process provides homogeneous dispersion of nanoparticles, alleviating agglomeration of nanoparticles, and reducing micro-crack/voids in matrix which can enhance their dielectric property. In this research, we demonstrated that by utilizing unique advantages of this material combination and a 3D printing technique, sensing capabilities for temperature and strain can be engineered with different content variations of included BT and CNTs. It is observed that the sensing capability for temperature change with respect to a 25–150℃ range can be improved as both BT and CNTs’ inclusions increase and is maximal with 1.7 wt.% CNTs/60 wt.% BT/PVDF nanocomposites, while the sensing capability for strain change in a 0–20% range is maximal with 1 wt.% CNTs/12 wt.% BT/PVDF nanocomposites. In addition, it is found that the best combination for mechanical toughness is 1 wt.% CNTs/12 wt.% BT/PVDF with 24.2 MPa and 579% in ultimate tensile strength and failure strain, respectively. These results show the technique to 3D print multifunctional nanocomposites with temperature and strain sensing capabilities as well as increased mechanical property. Furthermore, this research demonstrated the feasibility for large-scale multifunctional sensor device manufacturing with freedom of design, low-cost, and an accelerated process.

Presence of antibiotic contaminants in drinking water is increasing in epidemic proportions in recent times. Here, we report a scalable and cost-effective approach to prepare sulfonated saw dust (SD-SO3H) derived from saw dust (SD) that exhibits high-capacity adsorbent properties for the removal of antibiotics such as Tetracycline (TC), Sulfamethoxazole (SMX), and endocrine-disruptive chemicals such as Bisphenol A (BPA). The adsorption capacities of SD-SO3H towards the removal of TC, SMX, and BPA are 270.53 mg/g, 295.06 mg/g, and 263.75 mg/g, respectively. The adsorption capacity of SD-SO3H is about 2 and 4 times higher than commercially available activated carbon towards the removal of SMX and BPA, respectively according to the literature. For TC, the adsorption capacity of SD-SO3H is comparable to the commercially available activated carbon. The adsorbent was characterized using Scanning Electron Microscopy (SEM), Energy-dispersive X-ray Spectroscopy (EDS), Fourier Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy, Thermogravimetric analysis (TGA), and Zeta potential measurements. The effect of initial concentration, dosage, time, pH and temperature on the adsorption process was systematically investigated. Isotherms studies showed that the TC and SMX adsorption follow Langmuir isotherm whereas, BPA adsorption follows Freundlich isotherm. The kinetics data can be well defined by the pseudo-second order kinetic model. A thermodynamic study of adsorption showed that the TC adsorption process was endothermic while the SMX and BPA adsorption processes were exothermic, and the adsorption process was spontaneous in all cases. Altogether, SD-SO3H can be a scalable, cost-effective adsorbent for the efficient removal of TC, SMX and BPA from wastewater.

In this study, we report a facile method for the preparation of sulfonic acid functionalized carbonaceous adsorbent (TW-SO3H) from tea leaves. The adsorbent was characterized using Fourier-transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Energy-dispersive X-ray Spectroscopy (EDS), Thermogravimetric analysis (TGA), Raman Spectroscopy and Zeta potential measurements. The adsorbent was utilized for the adsorptive removal of antibiotics such as sulfamethoxazole (SMX) and endocrine disrupting chemicals such as bisphenol A (BPA) from water. The calculated adsorption capacities of TW-SO3H were 258.87 mg/g and 236.80 mg/g towards the removal of SMX and BPA, respectively at 25 °C. The new adsorbent has the ability to form electrostatic interaction and π–π stacking that allow the efficient adsorption of SMX and BPA. The Langmuir and Temkin isotherm models best fit the experimental data for the BPA and SMX adsorption processes, respectively. The results of the kinetic studies showed that the removal of SMX and BPA by TW-SO3H followed pseudo-second order kinetic model. A thermodynamic study indicated that the adsorption process was spontaneous as well as exothermic. The adsorbent was facilely regenerated and recycled for three cycles with a nominal loss of adsorption capacity. Our results indicated that TW-SO3H could be utilized as a promising adsorbent for the rapid removal of SMX and BPA from the contaminated water.

This research studied the effect of fused deposition modeling (FDM) 3D printing on three phase dielectric nanocomposites using poly(vinylidene) fluoride (PVDF), BaTiO3 (BT), and multiwall carbon nanotubes (CNTs). PVDF polymer and BT ceramics are piezo-, pyro- and di-electric materials extensively used for sensor and energy storage/harvesting applications due to their unique characteristic of dipole polarization. To increase dielectric property, CNTs have been recently utilized for uniform dispersion of BT nanoparticles, ultrahigh polarization density, and local micro-capacitor among matrix. It was proved that 3D printing process provides homogeneous dispersion of nanoparticles, alleviating agglomeration of nanoparticles and reducing micro-crack/voids in matrix which can potentially enhance their dielectric property than traditional methods. In this research, these three-phase nanocomposites are fabricated through FDM 3D printing process and characterized for dielectric property. Increasing both BT and CNT nanoparticles improves dielectric properties, while CNTs have a percolation threshold near 1.7 wt%. The most desirable combination of dielectric constant and loss properties (118 and 0.11 at 1 kHz) is achieved with nanocomposites containing 1.7 wt%-CNT/45 wt%-BT/PVDF. These results provide not only a technique to 3D print dielectric nanocomposites with improved dielectric property but also large-scale electronic device manufacturing possibility with freedom of design, low cost, and faster process.

Purpose The usage of additive manufacturing (AM) technology in industries has reached up to 50 per cent as prototype or end-product. However, for AM products to be directly used as final products, AM product should be produced through advanced quality control process, which has a capability to be able to prove and reach their desire repeatability, reproducibility, reliability and preciseness. Therefore, there is a need to review quality-related research in terms of AM technology and guide AM industry in the future direction of AM development. Design/methodology/approach This paper overviews research progress regarding the QC in AM technology. The focus of the study is on manufacturing quality issues and needs that are to be developed and optimized, and further suggests ideas and directions toward the quality improvement for future AM technology. This paper is organized as follows. Section 2 starts by conducting a comprehensive review of the literature studies on progress of quality control, issues and challenges regarding quality improvement in seven different AM techniques. Next, Section 3 provides classification of the research findings, and lastly, Section 4 discusses the challenges and future trends. Findings This paper presents a review on quality control in seven different techniques in AM technology and provides detailed discussions in each quality process stage. Most of the AM techniques have a trend using in-situ sensors and cameras to acquire process data for real-time monitoring and quality analysis. Procedures such as extrusion-based processes (EBP) have further advanced in data analytics and predictive algorithms-based research regarding mechanical properties and optimal printing parameters. Moreover, compared to others, the material jetting progresses technique has advanced in a system integrated with closed-feedback loop, machine vision and image processing to minimize quality issues during printing process. Research limitations/implications This paper is limited to reviewing of only seven techniques of AM technology, which includes photopolymer vat processes, material jetting processes, binder jetting processes, extrusion-based processes, powder bed fusion processes, directed energy deposition processes and sheet lamination processes. This paper would impact on the improvement of quality control in AM industries such as industrial, automotive, medical, aerospace and military production. Originality/value Additive manufacturing technology, in terms of quality control has yet to be reviewed.

The adsorptive removal of environmental pollutants is an effective method for the treatment of contaminated water. Thus, the preparation of adsorbents from low-cost, readily available, and renewable resources has garnered immense attention in recent years. In this study, a facile one-step method for the preparation of a high-capacity adsorbent is demonstrated by refluxing pine cones in concentrated sulfuric acid. With sulfuric acid reflux, the pine cones undergone carbonization as well as functionalization with sulfonic acid groups. The adsorbent demonstrated high adsorption capacity for two emerging organic pollutants, methylene blue (MB) and tetracycline (TC). Different variables such as pH, temperature, contact time, and initial concentration of the pollutants were analyzed and showed that the adsorption capacity for MB increased in a basic pH and vice versa for TC. Also, the elevated temperature favored the adsorption for both MB and TC. The maximum adsorption capacity was found to be 1666.66, and 357.14 mg g−1 for MB and TC, respectively. In comparison to the pristine pine cone, the sulfuric acid treated pine cone demonstrated an extraordinary improvement in the adsorption capacity. The adsorption of MB and TC was performed from the tap water matrix and similar adsorption capacities were found. A packed glass column was also prepared to demonstrate the adsorption of MB from tap water under flow conditions.

Multiwall carbon nanotubes (MWCNTs) are utilized to resolve low coupling coefficient issue by dispersing MWCNTs in poly(vinylidene fluoride) matrix to create stress reinforcing network, dispersant, and electron conducting functions for barium titanate (BT) nanoparticles. Various BT and MWCNT percentages of nanocomposite film are fabricated by FDM three-dimensional (3D) printing which can simplify the fabrication process as well as lower cost and design flexibility. Increasing MWCNTs and BT particles gradually increase piezoelectric coefficient (d31) by 0.13 pC/N with 0.4 wt%-MWCNTs/18 wt%-BT. These results provide not only a technique to print piezoelectric nanocomposites but also unique materials combination for sensor application.

Energy harvesting has drawn increasing attention due to the fast development of wireless sensors and devices. Most research has been focused on mechanical energy harvesting using piezoelectric ceramics; however, little is known on their experimental capabilities to harvest thermal energy at different temperature ranges and the impact that the temperature range has on the energy conversion efficiency. Majority of piezoelectric ceramics are pyroelectric in nature thus enabling them to couple energy between thermal and electrical domains. This paper demonstrates the use of Lithium Niobate (LNB) as a thermal energy harvesting device for high temperature applications. A custom testing setup was developed to test the LNB sample temperatures up to 225 °C. Pyroelectric coefficient of the material was characterized at different temperature ranges. Pyroelectric coefficient was found to increase with temperature, with a maximum value of −196 μC·m−2 °C−1. Power output of the sample was also characterized in different temperature ranges. A maximum value of over 20.5 μW was found when cycling the sample between 75 °C and 100 °C. Meanwhile, a maximum value of 14.8 μW was found in the 125 °C to 150 °C range. Finally, a peak value of 255 nW was found when cycling the sample in the 200 °C to 225 °C range.

Ethnopharmacological relevance Hovenia dulcis, known as the oriental raisin tree, is mainly found in East Asia. It has long been used as traditional folk remedies for alcohol intoxication. Aim of the study To examine the anti-hangover effect of Hovenia dulcis Thunb. fruit extract (HDE) in a randomized controlled crossover trial. Materials and methods Twenty-six eligible male adults with heterozygous ALDH2 (23.7±0.3 years old) consumed 360 mL of Korean Soju (50 g alcohol) together with HDE (2460 mg) or matched placebo with subsequent crossover. The blood samples were taken at baseline and 1, 4, and 12 h post-treatment. Results Blood alcohol, acetaldehyde, and total hangover scores were highest at 1 h post-treatment with no difference between groups, but declines in hangover symptom scores were significant in the HDE group compared to the placebo group. Significant differences between groups were also observed on interleukin (IL)-6, IL-10, IL-10/IL-6 ratio, and aspartate aminotransferase levels, but not on endotoxins. Pearson correlation analysis revealed a positive correlation between total hangover symptom scores and IL-6 and IL-10 level. Further analyses by CYP2E1 polymorphism at rs10776687, rs2031920, rs3813867, and rs4838767 alleles showed a reversed association, suggesting that CYP2E1 polymorphism might be an effect modifier. Conclusions The results suggest that a favorable effect of HDE on alcohol hangovers might be associated with enhancing homeostatic regulation of inflammatory response. The magnitude of impact might be different in the presence of CYP2E1 polymorphism.

Carbon based materials have long been investigated as anodes for lithium ion batteries. Among these materials, porous carbon holds several advantages such as high stability, high specific surface area, and excellent cycling capability. To further enhance the energy storage performance, ceramic nanomaterials have been combined with carbon based materials as hybrid anodes for enhanced specific capacity. The use of metal oxide ceramic nanomaterials could enhance the surface electrochemical reactivity thus leads to the increasing of capacity retention at higher number of cycles. In this research, we synthesized ceria (CeO2) nano-particles on porous carbon to form inorganic-organic hybrid composites as an anode material for Li-ion battery. The high redox potential of ceria is expected to increase the specific capacity and energy density of the system. The electrochemical performance was determined by a battery analyzer. It is observed that the specific capacity could be improved by 77% using hybrid composites anode. The material morphology, crystal structure, and thermal stability were characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), and Thermogravimetric Analysis (TGA).

The increasing demand for energy storage devices has propelled research for developing efficient super-capacitors (SC) with long cycle life and ultrahigh energy density. Carbon-based materials are commonly used as electrode materials for SC. Herein, we report a new approach to improve the SC performance utilizing a Porous Carbon/Cerium Oxide nanoparticle (PC-CON) hybrid as electrode material synthesized via a low temperature hydrothermal method. Through this approach, charges can be stored not only via electrochemical double layer capacitance (EDLC) from PC but also through pseudo-capacitive effect from CeO2 nanoparticles (NPs). The electrode-electrolyte interaction due to the electrochemical properties of the electrolyte provides an enhanced voltage window for the SC. Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), and X-Ray Diffraction (XRD) measurements were used for the characterization of this PC/CeO2 hybrid material system. The testing results have shown that a maximum of 500% higher specific capacitance could be obtained using PC/CeO2 instead of using PC only.

This paper presents a fabrication process to enhance homogeneous dispersion of BaTiO3 nanoparticles in polyvinylidene fluoride matrix nanocomposites using fused deposition modeling (FDM) 3D printing technique. The nanocomposites integrate the functional property (piezoelectric, pyroelectric, and dielectric) of BaTiO3 with the flexibility and lightweight of polyvinylidene fluoride. Traditionally, the simple yet effective way to fabricate the nanocomposites includes solvent-casting, spin-coating, and hot-embossing. However, these methods have disadvantages such as heterogeneous dispersion of BaTiO3 nanoparticles in polyvinylidene fluoride matrix due to the higher density of BaTiO3 compared with polyvinylidene fluoride and agglomeration during fabrication process. This heterogeneous dispersion could weaken functional and mechanical properties. Herein, fused deposition modeling 3D printing technique was utilized for homogeneous dispersion to alleviate the agglomeration of BaTiO3 in polyvinylidene fluoride through two processes: filament extrusion and 3D printing. In addition, thermal poling was applied to further enhance piezoelectric response of the BaTiO3/polyvinylidene fluoride nanocomposites. It is found that 3D printed BaTiO3/polyvinylidene fluoride nanocomposites exhibit three times higher piezoelectric response than solvent-casted nanocomposites.

While the use of TiO2 nanoparticles in the form of slurry/suspension requires energy-intensive separation processes, its immobilization in solid support may open new opportunities in the area of sustainable water treatment technologies. In this study, a novel method for the development of photocatalytic paint based on TiO

In this report, highly crystalline and well-dispersed nano-sized nickel metal organic framework (MOFs) was decorated over graphene oxide (GO) and carbon nanotubes (CNTs) platforms to form hybrid nanocomposites. These as-synthesized hybrid nanocomposites were synthesized through a one-pot green solvothermal method. The prepared nanocomposites were characterized by SEM, TEM, EDS, XRD, FT-IR, Raman and TGA techniques. XRD analysis revealed the crystalline structure of the hybrid nanocomposites. Morphological and elemental studies also verified successful decoration of nickel-benzene dicarboxylate (Ni-BDC) MOFs over GO and CNT platforms. Chemical analysis collected through IR, and thermal analysis collected through TGA technique, illustrated the presence of all the components in the hybrid nanomaterials. Methylene blue (MB) was used as a model organic pollutant to analyze the adsorption capacity of the prepared nanocomposites. According to the findings, a strong interaction exists between the MB molecule and the developed adsorbents at which due to the synergistic effect, the hybrid nanocomposites show several times higher adsorption capacity compared to that of parent materials. This improvement can be due to several reasons: high surface area of the MOFs in the composites resulting from the smaller size of MOFs, presence of the pores formed between the MOFs and the platforms and different morphological characteristic of Ni-BDC MOFs in hybrid nanocomposites, compared to bare Ni-BDC MOFs. Furthermore, the isotherm and kinetic studies revealed that the adsorption of MB onto the newly prepared adsorbents could best be explained by the Langmuir and Pseudo-second order kinetic models. A regeneration study demonstrated the highly stable nature of the hybrid nanocomposites.

While the use of TiO2 nanoparticles in the form of slurry/suspension requires energy-intensive separation processes, its immobilization in solid support may open new opportunities in the area of sustainable water treatment technologies. In this study, a novel method for the development of photocatalytic paint based on TiO2 nanoparticles and acrylate-based photopolymer resin is reported. The paint (TiO2@polymer) was applied on substrates such as plastic petri dish and glass jar, which was polymerized/solidified by ultraviolet light irradiation. The painted petri dish and glass jar were used for the photocatalytic degradation of model organic pollutants viz. methyl orange (MO), methylene blue (MB), and indole in deionized water, simulated fresh drinking water, and tap water matrices. The photocatalytic degradation studies were performed under sunlight and UV-B light were used for. The sunlight-assisted photocatalytic degradation of MO and MB was found to be faster and more efficient than the UV-B light-assisted ones. Under UV-B light irradiation, it took 120 min to degrade about 80% of 6 ppm MB solution, whereas under sunlight irradiation it took 60 min to degrade about 90% of the same MB solution. The photocatalytic paint generated hydroxyl radical (·OH) under the UV-B and sunlight irradiation, which was studied by the terephthalic acid fluorescence tests. Further, the potential release of TiO2 during the exposure to UV irradiation was studied by single particle ICP-MS analysis.

Supplemental material for Multifunctional SENSING using 3D printed CNTs/BaTiO3/PVDF nanocomposites by Hoejin Kim, Bethany R Wilburn, Edison Castro, Carlos A Garcia Rosales, Luis A Chavez, Tzu-Liang Bill Tseng and Yirong Lin in Journal of Composite Materials

In this work, a simple approach to 3D printing of carbon black based shape memory polymer nanocomposites (SMP/CB) with toughness improving capabilities during programing stage using electrical stimulus is reported. Conductive SMP/CB nanocomposites, consisting of commercial SMP filled with conductive CB nanoparticles, were fabricated using solvent casting and single screw extrusion processes. Subsequently, material extrusion (ME) technique was used to 3D print dog bones type IV specimens for tensile test and electrical stimulus. It was found that SMP/CB electrical conductivity can be tuned by the filler fraction. In addition, electrical current passing through SMP/CB nanocomposites causes temperature increments and changes on material strength condition. Temperature profiles at various electrical current levels are reported. Moreover, Young's modulus and toughness of the 3D printed specimens subjected and not subjected to electrical current are presented. It was observed that conductive SMP/CB specimens responded to electrical current stimulus by increasing their toughness four times higher than with no current applied during tensile test. This paper is a reference for rheological and conductive properties of SMP/CB nanocomposites fabricated by ME 3D printing process.

A new class of electronic materials derived predominantly from natural foods and foodstuffs, with minimal levels of inorganic materials, is developed and studied to build edible electronic components and devices compatible with the gastrointestinal (GI) tract. A “toolkit” of food-based electronic materials, fabrication schemes, basic device components, and functional devices with integrated sensing and wireless signal transmission is reported. These new materials establish the possibility to extend GI electronic devices beyond the ingested nondegradable systems to edible and nutritive systems, in which the described materials may be ingested and assimilated as metabolized nutrients. This study represents a new era of edible electronics with the potential to revolutionize modern biomedical technologies and devices.

This paper presents 3D printing of piezoelectric sensors using BaTiO3 (BTO) filler in a poly(vinylidene) fluoride (PVDF) matrix through electric in situ poling during the 3D printing process. Several conventional methods require complicated and time-consuming procedures. Recently developed electric poling-assisted additive manufacturing (EPAM) process paves the way for printing of piezoelectric filaments by incorporating polarizing processes that include mechanical stretching, heat press, and electric field poling simultaneously. However, this process is limited to fabrication of a single PVDF layer and quantitative material characterizations such as piezoelectric coefficient and β-phase percentage are not investigated. In this paper, an enhanced EPAM process is proposed that applies a higher electric field during 3D printing. To further increase piezoelectric response, BTO ceramic filler is used in the PVDF matrix. It is found that a 55.91% PVDF β-phase content is nucleated at 15 wt% of BTO. The output current and β-phase content gradually increase as the BTO weight percentage increases. Scanning electron microscopy analysis demonstrates that larger agglomerates are formulated as the increase of BTO filler contents and results in increase of toughness and decrease of tensile strength. The highest fatigue strength is observed at 3 wt% BTO and the fatigue strength gradually decreases as the BTO filler contents increases.

This paper presents a novel process to fabricate piezoelectric films from polyvinylidene fluoride (PVDF) polymer using integrated fused deposition modeling (FDM) 3D printing and corona poling technique. Corona poling is one of many effective poling processes that has received attention to activate PVDF as a piezoelectric responsive material. The corona poling process occurs when a PVDF polymer is exposed to a high electric field created and controlled through an electrically charged needle and a grid electrode under heating environment. FDM 3D printing has seen extensive progress in fabricating thermoplastic materials and structures, including PVDF. However, post processing techniques such as poling is needed to align the dipoles in order to gain piezoelectric properties. To further simplify the piezoelectric sensors and structures fabrication process, this paper proposes an integrated 3D printing process with corona poling to fabricate piezoelectric PVDF sensors without post poling process. This proposed process, named 'Integrated 3D Printing and Corona poling process' (IPC), uses the 3D printer's nozzle and heating bed as anode and cathode, respectively, to create poling electric fields in a controlled heating environment. The nozzle travels along the programmed path with fixed distance between nozzle tip and sample's top surface. Simultaneously, the electric field between the nozzle and bottom heating pad promotes the alignment of dipole moment of PVDF molecular chains. The crystalline phase transformation and output current generated by printed samples under different electric fields in this process were characterized by a Fourier transform infrared spectroscopy and through fatigue load frame. It is demonstrated that piezoelectric PVDF films with enhanced β-phase percentage can be fabricated using the IPC process. In addition, mechanical properties of printed PVDF was investigated by tensile testing. It is expected to expand the use of additive manufacturing to fabricate piezoelectric PVDF-based devices for applications such as sensing and energy harvesting.

A crossover design, with two repeated factors, is commonly used for analysing tolerance tests, i.e., measurements of physiologic response, following ingestion of some exogenous substance. For data analysis using a crossover design, a standard approach is to use linear mixed effect models (LMMs), as these can adequately handle correlated measurements from the crossover design. Alternatively, univariate analyses, using single summary statistics, can be employed for assessments such as the difference of measurements between time points, incremental area under curve (iAUC), Cmax etc. However, the use of summary measures may result in the loss of information. In this study, instead of using one single summary measure, we propose using multiple summary measures simultaneously through LMMs by taking their correlation into account. We compare the performance of the proposed method with other existing methods through real data analysis and simulation studies. We show that our proposed method has equivalent power to that of standard LMM approach, while using a much fewer number of parameters.