Composite Solid Polymer Research Articles

Microfluidics-assisted electrospinning of aligned nanofibers for modeling intestine barriers.

During electrospinning, the fibers deposited on the collector are usually randomly oriented in a disordered form. Researchers hope to generate periodic structures to expand the application of electrospinning, including improving the sensing properties of electronic and photonic devices, improving the mechanical properties of solid polymer composites and directional growth of human tissues. Here, we propose a technique to control the preparation of aligned foodborne nanofibers by placing dielectric polymers on microfluidic devices, which does not require the use of metal collectors. This study was conducted by introduced PEDOT:PSS polymer as a ground collector to prepare aligned foodborne nanofibers directly on the microfluidic platform. The fluidity of the electrolytic polymer collector makes it possible to shape the grounding collector according to the shape of the microcavity, thus forming a space adjustable nanofiber membrane with a controllable body. The simplicity of dismantling the collector also enables it extremely simple to obtain a complete electrospun fiber membrane without any additional steps. In addition, nanofibers can be easily stacked into a multi-layer structure with controllable hierarchical structures. The Caco-2 cells that grow on the device formed a compact intestinal epithelial layer that continuously expresses the tightly bound protein ZO-1. This intestinal barrier, which selectively filters small molecules, has a higher level of TEER, reproducing intestinal filtration functions similar to those of in vivo models. This method provides new opportunities for the design and manufacture of various tissue scaffolds, photonic and electronic sensors.

Electrical transport in PEO-NaI-NASICON nanocomposites: An assessment using impedance and X-Ray absorption spectroscopy

Present investigation focuses on conductivity-structure correlation in NaTi2(PO4)3 (NTP) embedded novel hybrid solid polymer composites prepared in a wide range of composition 10NaI-90(PEO1-xNTPx) (wt%), for 0 ≤ x ≤ 0.7. A maximum ionic conductivity of ˜ 4 × 10-5 Ω-1 cm-1 has been achieved with x = 0.7 at 40 °C that is higher than that of the host PEO-NaI (⁓ 5 × 10-7 Ω-1 cm-1) system by at least two orders of magnitude. Elemental mapping during field emission scanning electron microscopy suggests homogeneous distribution of NTP in the compositions. Trends of K-edge energies of oxygen in the X-Ray absorption near edge structure spectra have been found to be useful in proposing a tentative mechanism for ionic transport. Structural and impedance spectroscopy investigations suggest that for low NTP content, salt ions prefer to move through polymer. However, for higher content, surface states of NASICON at polymer-NTP interface facilitate the ionic conduction.

Temperature Regulation in Colored Infrared-Transparent Polyethylene Textiles

Summary Effectively regulating heat flow between the human body and its environment not only increases thermal comfort but also presents a novel and potentially cost-effective approach to reducing building energy consumption. Infrared property-engineered textiles have been shown to passively regulate radiative heat dissipation for effective cooling and warming of the human body. However, a lack of dyes that can tune the textile color without compromising the infrared properties remains a major impediment to textile commercialization. Here, we report a new strategy utilizing inorganic nanoparticles as a coloring component for scalable brightly colored, infrared-transparent textiles. The as-fabricated composite textiles not only show a high infrared transparency of ∼80% and a passive cooling effect of ∼1.6°C–1.8°C but also exhibit intense visible colors with good stability against washing. This facile coloration approach will promote the commercialization of radiative cooling textiles in temperature-regulating wearable applications for effective energy savings.

Dielectric relaxations and transport properties parameter analysis of novel blended solid polymer electrolyte for sodium-ion rechargeable batteries

A novel blended solid polymer electrolyte comprising polyethylene oxide and polyvinylpyrrolidone polymers for blending and sodium nitrate (NaNO3) as ion conducting species has been optimized via standard solution-cast technique. XRD, FESEM, and FTIR were performed to obtain the information about the structural changes, morphology, and microstructural changes (polymer–ion and ion–ion interactions) of the solid polymer electrolyte films. The electrochemical impedance spectroscopy, linear sweep voltammetry, and i–t characteristics were performed to evaluate the ionic conductivity, voltage stability window, and ion transference number. The impedance study was done in a broad temperature range (40–100 °C). The DSC and TGA were used to obtain information about the thermal transitions and thermal stability of prepared films. The ion dynamics is further investigated by analyzing the complex permittivity, loss tangent, and complex conductivity. All the plots were fitted through established theoretical model/expressions in whole frequency window to obtain dielectric strength, ion conduction path behavior, and relaxation time. Transport parameters such as number density (n), mobility (μ), and diffusion coefficient (D) of mobile ions were obtained by three methods and compared satisfactorily. Lastly, a coherent mechanism for the migration of charge transport carriers within the solid polymer composites has been proposed based on the performed experimental outcome.

Erratum to: Occurrence of electrical percolation threshold and observation of phase transition in chitosan(1−x):AgI x (0.05 ≤ x ≤ 0.2)-based ion-conducting solid polymer composites

Erratum to: Occurrence of electrical percolation threshold and observation of phase transition in chitosan(1−x):AgI x (0.05 ≤ x ≤ 0.2)-based ion-conducting solid polymer composites

Occurrence of electrical percolation threshold and observation of phase transition in chitosan(1−x):AgI x (0.05 ≤ x ≤ 0.2)-based ion-conducting solid polymer composites

This paper reports on the investigation of electrical percolation threshold and ion transport mechanism for ion-conducting solid polymer composites based on chitosan. The composite samples were prepared by solution cast technique. The result of DC conductivity versus percolation threshold (\(\varPhi^{ - 1/3}\) ) confirmed that at low AgI concentration, the tunneling effect governs ionic conduction mechanism. Nevertheless, at high filler concentration, the DC conductivity showed a plateau behavior. The DC conductivity as a function of reciprocal temperature revealed that the ion conduction mechanism is slightly temperature dependent and the ion–ion correlational effect is dominant. A steep increase in DC conductivity above 323 K is observed, which indicated the existence of some phase transition near the beta (β)-phase. The drop of DC conductivity at high temperatures is anticipated from the impedance plots. The AC conductivity spectrum exhibited three distinct regions at low temperatures. The high-frequency regions of AC conductivity spectra were almost temperature independent at low temperatures (303–323 K) and obeyed the Jonscher’s power law. The variation in frequency exponent versus temperature reveals that ion conduction mechanism follows QMT and CBH models at low and high temperatures, respectively. The valuable achievement of this work is that the temperature dependence of DC conductivity and the frequency exponent (s) is correlated to interpret the Ag+ ion dynamic and ion–ion correlational effect. The Argand plots were used to explain the relaxation processes.

The Compaction of Fibrous Fillers under Pressure and the Structure Formation in Reinforced Organoplastics during Processing

An examination has been made of questions of the compaction and structure formation under forming pressure of reinforcing organic and traditional (carbon, glass) fibrous fillers. The laws governing the compaction of the different reinforcing fibres under pressure were established, the possibilities of purposeful change in the structure of the reinforced polymeric materials during forming under pressure were shown, and the conditions of production of solid polymer composites of reinforced structure with fibrous fillers were also established.

Tuning the absorption of ultraviolet spectra and optical parameters of aluminum doped PVA based solid polymer composites

In this research work PVA:xAl (0.01 ≤ x ≤ 0.05) based solid polymer composites have been prepared by solution cast technique. The transmittances of the samples are decreased with increasing Al powder concentration. The absorption spectra of the samples are shifted to higher wavelengths which indicate their importance for shielding. The increase of absorption intensity in UV region was observed. The clear shift of absorption edge upon the addition of Al powder content indicated the decrease of energy band gap. The increase of extinction coefficient at high wavelengths for the samples containing Al powder revealed the loss of photon energy. The refractive indexes of the doped samples are increased compared to that of pure PVA. The linear relationship between the refractive index and volume fraction indicates a good dispersion of Al powder in PVA host polymer. The direct optical band gap measured from the plot of (αhυ)2 versus photon energy (hυ) showed a decreasing trend with increase of Al content. The Urbach energy was found to increase with increasing aluminum concentration. The complex optical dielectric functions were used to determine the type of electron transition.

Optical Characteristics of Polystyrene Based Solid Polymer Composites: Effect of Metallic Copper Powder

Solid polymer composites (SPCs) were prepared by solution cast technique. The optical properties of polystyrene doped with copper powder were performed by means of UV-Vis technique. The optical constants were calculated by using UV-Vis spectroscopy. The dispersion regions were observed in both absorption and refractive index spectra at lower wavelength. However, a plateau can be observed at high wavelengths. The small extinction coefficient compared to the refractive index reveals the transparency of the composite samples. The refractive index and optical band gap were determined from the reflectance and optical absorption coefficient data, respectively. The nature of electronic transition from valence band to conduction band was determined and the energy band gaps of the solid composite samples were estimated. It was observed that, upon the addition of Cu concentration, the refractive index increased while the energy gaps are decreased. The calculated refractive indexes (low index of refraction) of the samples reveal their availability in waveguide technology.

Thermal, mechanical and electrical properties of the PEO-based solid polymer electrolytes filled by yttrium oxide nanoparticles

The novel composite lithium solid polymer electrolytes (SPEs) composed of polyethylene oxide (PEO) matrix and yttrium oxide (Y2O3) nanofillers were prepared by a solution casting method. The crystal morphology of the SPEs was characterized by polarized optical microscope (POM) and wide-angle X-ray diffraction (WAXD). The induced nucleation and steric hindrance effects of Y2O3 nanofillers result in the increased amount as well as decreased size of PEO spherulites which are closely related to the crystallinity of the SPEs. As the Y2O3 contents increase from 0 wt% to 15 wt%, the crystallinity of the SPEs decreases proportionally. The thermal, mechanical and electrical properties of the SPEs were investigated by thermal gravimetric analysis (TGA), dynamic mechanical analysis (DMA) and AC impedance method, respectively. The physical properties including thermal, mechanical and electrical performances, depending remarkably on the polymer-filler interactions between PEO and Y2O3 nanoparticles, are improved by different degrees with the increase of Y2O3 contents. The (PEO)21LiI/10 wt%Y2O3 composite SPE exhibits the optimal room-temperature ionic conductivity of 5.95×10−5 S·cm−1, which satisfies the requirements of the conventional electrochromic devices.

Effect of co-doping nano-silica filler and N-methyl- N-propylpiperidinium bis(trifluoromethanesulfonyl)imide into polymer electrolyte on Li dendrite formation in Li/poly(ethylene oxide)-Li(CF 3SO 2) 2N/Li

Lithium metal dendrite growth in Li/poly (ethylene oxide)-lithium bis (trifluoromethanesulfonyl) imide (PEO 18LiTFSI), nano-silica, and N-methyl- N-propylpiperidinium bis(trifluoromethanesulfonyl)imide (PP13TFSI) composite solid polymer electrolyte/Li was investigated by direct in situ observation. The dendrite onset time decreased with increasing current density and deviated from Sand's law in the current density range of 0.1–0.5 mA cm −2 at 60 °C. Lithium dendrite formation was not observed until 46 h of polarization at 0.5 mA cm −2 and 60 °C, which is a significant improvement compared to that observed in Li/(PEO 18LiTFSI)/Li, where the dendrite formation was observed after 15 h polarization at 0.5 mA cm −2 and 60 °C. The suppression of dendrite formation could be explained by the electrical conductivity enhancement and decrease of the interface resistance between Li and the polymer electrolyte by the introduction of both nano-SiO 2 and PP13TFSI into PEO 18LiTFSI. The electrical conductivity of 4.96 × 10 −4 S cm −1 at 60 °C was enhanced to 7.6 × 10 −4 S cm −1, and the interface resistance of Li/PEO 18LiTFSI/Li of 248 Ω cm 2 was decreased to 74 Ω cm 2 by the addition of both nano-SiO 2 and PP13TFSI into PEO 18LiTFSI.

Lithium Dendrite Formation in Li/Poly(ethylene oxide)–Lithium Bis(trifluoromethanesulfonyl)imide and N-Methyl-N-propylpiperidinium Bis(trifluoromethanesulfonyl)imide/Li Cells

Lithium metal dendrite growth in Li/poly(ethylene oxide)–lithium bis(trifluoromethanesulfonyl)imide and in an ionic liquid, -methyl--propylpiperidinium bis(trifluoromethanesulfonyl)imide (PP13TFSI) composite solid polymer electrolyte/Li was examined by direct in situ observation. Lithium dendrite formation was observed after 15 h of polarization at and at on . The onset time was increased to 35 h at by the addition of PP13TFSI into up to 1.44 mol. The dendrite onset time decreased with increasing current density and deviated from Sand’s law in the current density range of at . The electrical conductivity of was enhanced, and the interface resistance between Li and was suppressed by the addition of PP13TFSI. The lithium ion transport number of the composite electrolyte decreased with increasing in . The suppression of the lithium dendrite formation could be explained by the low resistance of the interface layer between lithium and the composite polymer electrolyte.

Effect of radiation on conductivity of solid PVA–KOH–PC composite polymer electrolytes

The aim of this work is to enhance the room temperature conductivity of solid alkaline composite polymer electrolytes (ACPEs) based on polyvinyl alcohol/potassium hydroxide/propylene carbonate (PVA–KOH–PC) composites by cross-linking the PVA and bond scission of the PC by γ-radiation. The ACPEs were prepared by solvent-casting technique and irradiated with doses up to 200 kGy at room temperature. The microstructure of the ACPEs was measured using XRD spectrometer, and the results show the structural change from semicrystalline to amorphous, indicating that the cross-linking has been achieved at higher doses. It was found that the PKOH composite at 40 wt% KOH and PPC composite at 60 wt% PC show higher conductivities. The conductivity of the PKPC composites is dominated by dc conductivity at higher frequencies and that PC with 60 wt% has the highest conductivity at a dose of 200 kGy.

Preparation of amide and amine groups containing copolymers of methyl methacrylate and their performance in solid polymer composites

AbstractMethyl methacrylate (MMA) was copolymerized with acrylamide, N‐methylacrylamide, N,N‐dimethylacrylamide, 1‐vinyl‐2‐pyrrolidone, 4‐vinylpyridine, and 2‐dimethylaminomethyl methacrylate in 1,4‐dioxane solution at 65°C, using AIBN as initiator, to yield copolymers with comonomer contents between about 5 and 50 mole‐%. The monomer reactivity ratios were evaluated. The copolymerizations are in general non‐azeotropic and non‐ideal. The amine group containing comonomers are preferentially incorporated in relation to MMA, but MMA is preferentially incorporated in relation to the amide group containing comonomers. The average molecular weights of the copolymers, with the exception of the N,N‐dimethylacrylamide copolymer, decrease with increasing comonomer concentration, especially in the case of the amine group containing comonomers. The increasing content of amide and amine group containing monomeric units in the copolymers influences the adsorption of the polymers on an iron oxide red pigment, the dispersion stability, as well as the adhesion of the polymer coatings on steel plates and their corrosion protection.