Polymer Network Structure Research Articles

Anion-Immobilized Gel Polymer Electrolyte with a High Ion Transference Number for High-Performance Lithium/Sodium Metal Batteries.

Due to their high energy density, lithium/sodium metal batteries (LMBs/SMBs) are expected to be the next generation of energy storage systems. However, the further application of alkali metal batteries based on liquid electrolytes is limited due to increasing safety concerns. Gel polymer electrolytes (GPEs), which combine the advantages of the high ionic conductivity of liquid electrolytes and excellent mechanical properties of solid polymer electrolytes, are considered to play an irreplaceable role in the realization of high-performance alkali metal batteries. In this work, a flexible boron-containing GPE (B-GPE) with a cross-linked polymer network structure is prepared by a UV-induced process. The as-prepared B-GPE exhibits good ionic conductivity and has an extremely high ion transference number due to the electron-withdrawing effect of the boron moiety and the facile electrolyte uptake ability of the ethylene oxide chain. Furthermore, a "gentle" electrode/electrolyte contact is designed by a one-step in situ polymerization method, which can enhance ion transport within the electrode and at the electrode/electrolyte interface due to the presence of a continuous polymer phase for ion conduction. Therefore, LMBs and SMBs containing B-GPE are able to effectively inhibit the growth of dendrites while exhibiting excellent cycling stability. These comprehensive results indicate that this novel B-GPE possesses potential applications for high-performance alkali metal batteries.

Polymeric Hydrogels for Intervertebral Disc Replacement/Integration: Playing with the Chemical Composition for Tuning Shear Behavior and Hydrophilicity.

Damages to the intervertebral disc (IVD) due to improper loading or degeneration result in back pain, which is a common disease affecting an increasing number of patients. Different strategies for IVD remediation have been developed, from surgical treatment to disc replacement, by using both metallic and non-metallic materials. Hydrogels are very attractive materials due to their ability to simulate the properties of many soft tissues; moreover, their chemical composition can be varied in order to assure performances similar to the natural disc. In particular, for the replacement of the IVD outer ring, namely, the anulus fibrosus, the shear properties are of paramount importance. In this work, we produced hydrogels through the photo-induced crosslinking of different mixtures composed of two hydrophilic monofunctional and difunctional polymers, namely, poly(ethyleneglycol) methyl ether methacrylate (PEGMEMA) and poly(ethyleneglycol) dimethacrylate (PEGDMA), together with a hydrophobic molecule, i.e., tert-butyl acrylate (tBA). By changing the ratio among the precursors, we demonstrated the tunability of both the shear properties and hydrophilicity. The structural properties of hydrogels were studied by solid-state nuclear magnetic resonance (NMR). These experiments provided insights on both the structure and molecular dynamics of polymeric networks and, together with information obtained by differential scanning calorimetry (DSC), allowed for correlating the physical properties of the hydrogels with their chemical composition.

Effects of glycerol and PVA on gelatin/Gum Arabic aerogels: Microstructure, mechanical properties, and applications for food monitoring

Smart labels are a hot research topic in the field of food science, but the low sensitivity of film smart labels limits the on-site and visual detection of seafood freshness. To address these challenges, betacyanin (BET) as a response signal and an aerogel smart label based on gelatin/gum arabic (Gel/GA) were designed. The labels produced a visually observable color change in the presence of volatile ammonia (2500 ppm) and displayed an immediate colorimetric response to food spoilage when packaged shrimp was used as an example. The results showed that the smart aerogel labels were better than the film smart labels in the response sensitivity test of volatile ammonia. In addition, the addition of a small amount of plasticizers (glycerol) or hardeners (polyvinyl alcohol, PVA) further enhanced the responsiveness of the aerogel to volatile ammonia. Notably, the addition of a small amount of PVA further increased the hardness of the aerogels. The scanning electron microscopy (SEM), infrared spectroscopy, and X-ray diffraction (XRD) results showed that these results may be caused by the interpenetration of the PVA network and the Gel/GA network to form a new type of interpenetrating polymer network structure. Therefore, the developed smart aerogel labels play an important role in ensuring food quality and reducing food waste and inspire new ideas for the development of additional functional smart labels.

Performance and Mechanism of Using Low-Cost Fumed Silica Nanoparticles in Enhancing High Viscosity Modified Asphalt

Fumed silica nanoparticles (FSNPs) have shown significant potential in polymer modification due to their economic viability. This study aims to explore the impact of FSNPs on the performance of high viscosity modified asphalt (HVMA). For a comprehensive view, we also introduced Nano-SiO2 and Nano-TiO2, common nano-modifiers, for comparison with the results achieved by FSNPs. The morphology of these nano-modifiers was observed with Field Emission Scanning Electron Microscopy (FESEM). The changes in rheological, chemical, and thermal properties of HVMA before and after modification were evaluated using techniques such as Dynamic Shear Rheometer (DSR), Fluorescence Microscope, Fourier Transform Infrared Spectroscopy (FTIR), and Thermogravimetric Analysis-Differential Scanning Calorimetry (TGA-DSC). The FESEM results revealed that FSNPs form a branchlike network while Nano-SiO2 and Nano-TiO2 lack specific structures or clear interconnections. Further rheological testing reveals that, when compared to Nano-SiO2 and Nano-TiO2, FSNPs improve the high-temperature performance of HVMA by 2–3 times and bolster its fatigue resistance by 1.2–3 times, while reducing temperature sensitivity. These enhancements are attributed to the synergistic strengthening between the FSNP's branchlike network and the SBS polymer network structure, underlining the significance of FSNPs' shape and connectivity in HVMA rheological property improvement.

Evaluation of the Effect of Honey-Containing Chitosan/Hyaluronic Acid Hydrogels on Wound Healing.

The 3D polymeric network structure of hydrogels imitates the extracellular matrix, thereby facilitating cell growth and differentiation. In the current study, chitosan/hyaluronic acid/honey coacervate hydrogels were produced without any chemicals or crosslinking agents and investigated for their wound-healing abilities. Chitosan/hyaluronic acid/honey hydrogels were characterized by FTIR, SEM, and rheology analysis. Moreover, their water content, water uptake capacities, and porosity were investigated. In FT-IR spectra, it was discovered that the characteristic band placement of chitosan with hyaluronic acid changed upon interacting with honey. The porosity of the honey-containing hydrogels (12%) decreased compared to those without honey (17%). Additionally, the water-uptake capacity of honey-containing hydrogels slightly decreased. Also, it was observed that hydrogels' viscosity increased with the increased hyaluronic acid amount and decreased with the amount of honey. The adhesion and proliferation of fibroblast cells on the surface of hydrogel formulations were highest in honey-containing hydrogels (144%). In in vivo studies, wound healing was accelerated by honey addition. It has been demonstrated for the first time that honey-loaded chitosan-hyaluronic acid hydrogels, prepared without the use of toxic covalent crosslinkers, have potential for use in wound healing applications.

Unique Polymer-Stabilized Liquid Crystal Structure Prepared by Addition of a Reversible Addition-Fragmentation Chain Transfer Agent.

Polymer-stabilized liquid crystals (PSLCs) are important electrically switchable materials due to their superior electro-optical properties. Nevertheless, it remains a formidable challenge to balance PSLCs' instant electro-optical performance and long-term durability due to their relatively low polymer content and the related sensitivity to external force. Herein, we demonstrate the possibility of regulating the polymer network structure in PSLCs via reversible addition-fragmentation chain transfer (RAFT) polymerization reactions of acrylate monomers with a chain transfer agent (CTA). By controlling the concentration of CTA and conditions of photopolymerization, the kinetics of the polymerization reaction can be modified. Compared to conventional free-radical (FR) polymerization, the reduced chain growth rate leads to sufficient chain relaxation, reorientation of liquid crystal (LC) directors, and alleviation of shrinkage stresses in the RAFT polymerization process. This in turn produces an ordered polymer network structure in the vertical direction and a uniform distribution in the horizontal plane. As a result, the PSLC network presents increased elasticity with a lower hysteresis effect and greatly improved durability. Our research offers insightful guidance for the fine-tuning of polymer network structures to prepare advanced LC/polymer composite structures with outstanding performances.

Accelerated ion transportation in liquid crystalline polymer networks for superior solid-state lithium metal batteries

The application of solid polymer electrolyte in high energy density lithium metal batteries is limited by low Li+ mobility, low ionic conductivity and poor cycle stability at room temperature. In the study, the free-standing flexible polymeric electrolytes (PCREs) with semi-interpenetrating-network in the topological nanostructures were fabricated through the in-situ UV-photopolymerization of the liquid crystalline monomers and poly(ethylene glycol) diglycidyl ether. Remarkably, by optimizing the relative proportion of the two liquid crystalline monomers with different methylene chains as connected bridge band between rigid center and terminal acrylate functional groups, the electrochemical properties of the prepared PCREs were successfully improved, which might contributed to the suitable ion transport channels in the porous polymer network structures. The prepared PCRE exhibited increased ion migration number, excellent ionic conductivity and a wide electrochemical window. Through the calculation of density functional theory and molecular dynamics simulation, the difference in the molecular orbital of liquid crystalline polymers and the mechanism of PCREs enhancement tLi+ were well understood. The study may provide new perspectives for the design and fabrication of high-performance polymer electrolyte materials, which will promote the development and practical application of the all-solid lithium metal batteries.

Generation of helical multi-functional microfiber motors based on modified microfluidic spinning method

Due to unique asymmetric shapes and easily realized directional movements, helical micromotors are widely used in applications such as drug delivery, cell manipulation, and wastewater purification. However, most of the hydrogel helical microfiber motors were water-based and had a homogeneous polymer network structure, which limited their practical applications like drug release. In this study, an emulsion-based microfluidic spinning method was used to prepare heterogenous helical hydrogel microfiber motors. Fine oil-in-water (O/W) emulsions were used as the inner phase of the microfluidic spinning process. When dichloromethane was used, micromotors with porous structure were formed after solidification and volatilization, improving the catalytic degradation rate of pollutants in water treatment application. When soybean oil was used, fat-soluble drugs were encapsulated successfully and gradually released as the micromotor degraded. Besides, the diameter and pitch size of the prepared fibers could be easily adjusted, and mass manufacturing (>100 m) was achieved.

Interplay between entanglement and crosslinking in determining mechanical behaviors of polymer networks

ABSTRACT In polymer physics, the concept of entanglement refers to the topological constraints between long polymer chains that are closely packed together. Both theory and experimentation suggest that entanglement has a significant influence on the mechanical properties of polymers. This indicates its promise for materials design across various applications. However, understanding the relationship between entanglement and mechanical properties is complex, especially due to challenges related to length scale constraints and the difficulties of direct experimental observation. This research delves into how the polymer network structure changes when deformed. We specifically examine the relationship between entanglement, crosslinked networks, and their roles in stretching both entangled and unentangled polymer systems. For unentangled polymers, our findings underscore the pivotal role of crosslinking bond strength in determining the system’s overall strength and resistance to deformation. As for entangled polymers, entanglement plays a pivotal role in load bearing during the initial stretching stage, preserving the integrity of the polymer network. As the stretching continues and entanglement diminishes, the responsibility for bearing the load increasingly shifts to the crosslinking network, signifying a critical change in the system’s behavior. We noted a linear correlation between the increase in entanglement and the rise in tensile stress during the initial stretching stage. Conversely, the destruction of the network correlates with a decrease in tensile stress in the later stage. The findings provide vital insights into the complex dynamics between entanglement and crosslinking in the stretching processes of polymer networks, offering valuable guidance for future manipulation and design of polymer materials to achieve desired mechanical properties.

Capsaicin-based silicone antifouling coating with enhanced interlocking adhesion via SIPN

Silicone-based coatings generally exhibit excellent dynamic fouling release due to their low surface energy and elastic modulus. However, the poor adhesion of these coatings at the interface between the coating and the substrate, as well as deficient static antifouling capabilities, severely deteriorate their antifouling properties over extended periods. Herein, an epoxy-poly(dimethylsiloxane)/capsaicin (EP-PDMS/CAP) coating with highly enhanced interfacial adhesion and remarkable antifouling performances was prepared. The coating adhesion strength of the EP-PDMS/CAP has been improved by more than 5 times compared to a PDMS control coating (from 0.4 MPa to 2.04 MPa) by forming a semi-interpenetrating polymer network (SIPN) structure between the epoxy and PDMS layers. The EP-PDMS/CAP coating achieved the superior antifouling effects in both static and dynamic conditions, the anti-bacterial rate was as high as 96.8 %, and the anti-algal adhesion rate to the green algae Chlorella increased by 95.7 %, due to the synergistic effects of the fouling release performance from the PDMS coating and the fouling prevention of capsaicin. Furthermore, the EP-PDMS/CAP coating was proven to be extremely stable in different treatments such as acid/basic solutions, air oven heating test, and cyclic sand abrasion, showing great potential for anti-biofouling under aggressive conditions. This work provides a promising pathway towards the development of high-performance silicone-based composite coatings for efficient marine anti-biofouling.

Preferential Mechanochemical Activation of Short Chains in Bidisperse Triblock Elastomers.

Polymer mechanochemistry offers attractive opportunities for using macroscopic forces to drive molecular-scale chemical transformations, but achieving efficient activation in bulk polymeric materials has remained challenging. Understanding how the structure and topology of polymer networks impact molecular-scale force distributions is critical for addressing this problem. Here we show that in block copolymer elastomers the molecular-scale force distributions and mechanochemical activation yields are strongly impacted by the molecular weight distribution of the polymers. We prepare bidisperse triblock copolymer elastomers with spiropyran mechanophores placed in either the short chains, the long chains, or both and show that the overall mechanochemical activation of the materials is dominated by the short chains. Molecular dynamics simulations reveal that this preferential activation occurs because pinning of the ends of the elastically effective midblocks to the glassy/rubbery interface forces early extension of the short chains. These results suggest that microphase segregation and network strand dispersity play a critical role in determining molecular-scale force distributions and suggest that selective placement of mechanophores in microphase-segregated polymers is a promising design strategy for efficient mechanochemical activation in bulk materials.

Evaluation of shape memory effect in PLA/copolymers blends

AbstractIn this work, polylactic acid (PLA)/copolymer blends were prepared by melt blending. Ethylene‐glycidyl methacrylate (E‐GMA) and ethylene‐butyl acrylate‐maleic anhydride (EBA‐MAH) functional block copolymers were used. A ternary blend of PLA/E‐GMA/EBA‐MAH was also studied. FTIR analyses evidenced the occurrence of reactive compatibilization of E‐GMA and EBA‐MAH with PLA in the binary blends due to the reactivity of the GMA and MAH functional groups with the terminal hydroxyl and carboxyl groups of PLA. Rheological measurements evidenced the occurrence of cross‐link reactions between E‐GMA and EBA‐MAH copolymers in the ternary blend. Three distinct morphologies were observed in the blends: PLA/E‐GMA exhibited a sea‐island structure, PLA/EBA‐MAH exhibited a co‐continuous structure, and PLA/E‐GMA/EBA‐MAH exhibited a semi‐interpenetrating polymer network (SIPN) structure. The shape memory effect (SME) of PLA and PLA/copolymers blends was evaluated by three different methods: fold‐deploy, tension, and torsion. Fold‐deploy tests were conducted in a water bath, whereas the tension and torsion tests were conducted using a rheometer. All methods proved to be effective; however, some precautions must be taken to choose the most suitable test for a given purpose, which is thoroughly discussed in this work. The SME of PLA was enhanced through the incorporation of the copolymers. Blending PLA with E‐GMA, EBA‐MAH, and E‐GMA/EBA‐MAH copolymers increased its shape recovery from 32% to 84%, 79.2%, and 80%, respectively, while its shape fixity remained around 100%.

Skin-adhesive lignin-grafted-polyacrylamide/hydroxypropyl cellulose hydrogel sensor for real-time cervical spine bending monitoring in human-machine Interface

Developing a straightforward method to produce conductive hydrogels with excellent mechanical properties, self-adhesion, and biocompatibility remains a significant challenge. While current approaches aim to enhance mechanical performance, they often require additional steps or external forces for fixation, leading to increased production time and limited practicality. A novel lignin-grafted polyacrylamide/hydroxypropyl cellulose hydrogel (L-g-PAM/HPC hydrogel) with a semi-interpenetrating polymer network structure had been developed in this research that boasted exceptional adhesion to the skin (∼68 kPa) and stretchability properties (∼1637 %) compared to PAM-based hydrogels. By incorporating conductive additives such as silver nanowires and carbon nanocages to construct a bridge-like structure within the hydrogel matrix, the resulting AgC@L-g-PAM/HPC hydrogel exhibited impressive electrical conductivity, surpassing that of other PAM-based hydrogels relying on MXene, with a maximum value of 0.76 S/m. Furthermore, the AgC@L-g-PAM/HPC hydrogel retained its efficient electrical signal transmission capability even under mechanical stress. These make it an ideal flexible strain sensor capable of detecting various human motions. In this study, a smart real-time monitoring system was successfully developed for tracking cervical spine bending, serving as an extension for monitoring human activities.

Developing 3D-network gels from polysaccharide gums for biomedical applications

Keeping in view the recent advancements in polysaccharide materials, gum acacia (GA) - tragacanth gum (TG) was investigated for designing polymeric network structures impregnated with cephalexin antibiotics for drug delivery (DD). Grafted product of polyvinylimidazole [poly(VIm)] and GA-TG was characterized by field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermo-gravimetric analysis (TGA) and differential scanning calorimetry (DSC). Change in mesh size (from 17.73 to 32.98 nm) and crosslinking density (between 1.64 × 10−5 to 5.06 × 10−5 mol cm−3) was found with change in poly(VIm), gum and crosslinker NNMBA content which revealed that these parameters can be tailored made as per requirement and applications. Swelling properties illustrated pH sensitivity in copolymers because of composition which is useful for colon or site-specific DD of cephalexin. FESEM and AFM demonstrated heterogeneous morphology with the rough surface topology of grafted product. XPS and FTIR confirmed the grafting of poly(VIm) onto polysaccharide chains. Drug diffusion was non-Fickian and release was fitted in Higuchi kinetic model from copolymers. The release was slow and prolonged due to drug-polymer interactions. Copolymers exhibited 31.29% scavenging ability in DPPH assay and haemolysis was less than 2% that inferred biocompatible nature. Bio-surface interactions with intestinal membrane indicated the muco-adhesive nature of copolymers. Antimicrobial properties of hydrogel were evaluated against E. coli, P. aeruginosa and S. aureus. All observations revealed that GA-TG crosslinked copolymers could be explored for colon DD of antibiotic drugs with tailored crosslinking density.

Low oil Pickering emulsion gels stabilized by bacterial cellulose nanofiber/soybean protein isolate: An excellent fat replacer for ice cream

Food-grade Pickering emulsion gels with different oil phase fractions stabilized by Bacterial cellulose nanofibers/Soy protein isolate complex colloidal particles were prepared by one-step method. The properties of Pickering emulsion gels with different oil phase fractions (5 %, 10 %, 20 %, 40 %, 60 %, 75 %, v/v) and their applications in ice cream were investigated in the present study. The microstructural results showed that Pickering emulsion gels with the low oil phase fractions (5 %–20 %) were an emulsion droplet-filled gel, where the oil droplets were embedded in the network structure of cross-linked polymer, while Pickering emulsion gels with higher oil phase fractions (40 %–75 %) were an emulsion droplet-aggregated gel, which formed a network structure by flocculated oil droplets. The rheology result showed that the low oil Pickering emulsion gels had the same excellent performance as the high oil Pickering emulsion gels. Furthermore, the low oil Pickering emulsion gels showed good environmental stability under harsh conditions. Consequently, Pickering emulsion gels with 5 % oil phase fraction were used as fat replacers in ice cream and ice cream with different fat replacement rates (30 %, 60 % and 90 %, w/w) was prepared in this work. The results showed the appearance and texture of the ice cream with low oil Pickering emulsion gels as fat replacers was similar to that of the ice cream with no fat replacers, and the melting rate of the ice cream with low oil Pickering emulsion gels as fat replacers showed the lowest value of 21.08 % during the 45 min of melting experiment, as the fat replacer rate in the ice cream reached to 90 %. Therefore, this study demonstrated that low oil Pickering emulsion gels were excellent fat replacers and had great potential application in low calorie food production.

Simultaneous High Ionic Conductivity and Lithium-Ion Transference Number in Single-Ion Conductor Network Polymer Enabling Fast-Charging Solid-State Lithium Battery.

Developing solid-state electrolyte with sufficient ionic conduction and flexible-intimate interface is vital to advance fast-charging solid-state lithium batteries. Solid polymer electrolyte yields the promise of interfacial compatibility, yet its critical bottleneck is how to simultaneously achieve high ionic conductivity and lithium-ion transference number. Herein, single-ion conducting network polymer electrolyte (SICNP) enabling fast charging is proposed to positively realize fast lithium-ion locomotion with both high ionic conductivity of 1.1 × 10-3 S cm-1 and lithium-ion transference number of 0.92 at room temperature. Experimental characterization and theoretical simulations demonstrate that the construction of polymer network structure for single-ion conductor not only facilitates fast hopping of lithium ions for boosting ionic kinetics, but also enables a high dissociation level of the negative charge for lithium-ion transference number close to unity. As a result, the solid-state lithium batteries constructed by coupling SICNP with lithium anodes and various cathodes (e.g., LiFePO4 , sulfur, and LiCoO2 ) display impressive high-rate cycling performance (e.g., 95% capacity retention at 5 C for 1000 cycles in LiFePO4 |SICNP|lithium cell) and fast-charging capability (e.g., being charged within 6min and discharged over than 180min in LiCoO2 |SICNP|lithium cell).Ourstudy provides a prospective direction for solid-state electrolyte that meets the lithium-ion dynamics for practical fast-charging solid-state lithium batteries.

Synthesis and adsorption behaviors of dendrimeric cross-linked networks with bio-based phytic acid groups obtained by UV curing

The treatment of wastewater, which has become a major environmental concern as industry has grown, is an important research topic. In this study, a dendrimeric cross-linked network had been designed as a new adsorbent for the removal of Crystal violet dye (CV) from aqueous solutions. First, dendrimers of the polyamidoamine (PAMAM) type with an ethylene diamine core were developed. Then, glycidyl metacrylate (GMA) was independently used to modify bio-based phytic acid and PAMAM dendrimer. The formation of a polymeric network structure with phosphoric acid groups that may be employed as an adsorbent (PG-PAG) was then accomplished using the UV curing. Nuclear Magnetic Resonance Spectroscopy (NMR), and Fourier-Transform Infrared-Attenuated Total Reflection (FTIR-ATR) were employed to characterize the polyester polymers. Differential Scanning Calorimetry (DSC), SEM-EDX (Scanning Electron Microscope-Energy Dispersion Spectroscopy), and Brunauer-Emmet-Teller surface measurement analysis (BET) were used to analyze the polymeric networks. The adsorbent’ adsorption and desorption behavior were examined. In this adsorption mechanism, which conforms to the Langmuir isotherm model, the theoretical capacity was calculated as 250 mg/g. In addition, kinetically suitable for the pseudo-second-order model was determined. According to the findings, this novel adsorbent may be used regardless of the pH of the aqueous media. Furthermore, in contrast to previously studied bio-based adsorption materials, the materials used in this study have extraordinarily high adsorptive capabilities. According to the pseudo-second-order model, theoretical 555.55 mg/g and experimental 530.43 mg/g capacities were found.

Conceptualization and Investigation of Multicomponent Polymer Networks as Prospective Corticosteroid Carriers.

Dexamethasone (DXM) is a highly potent and long-acting synthetic glucocorticoid with anti-inflammatory, anti-allergic, and immunosuppressive effects. However, the systemic application of DXM can cause undesirable side effects: sleep disorders, nervousness, heart rhythm disorders, heart attack, and others. In the present study, multicomponent polymer networks were developed as potential new platforms for the dermal application of dexamethasone sodium phosphate (DSP). First, a copolymer network (CPN) comprising hydrophilic segments of different chemical structures was synthesized by applying redox polymerization of dimethyl acrylamide onto poly(ethylene glycol) in the presence of poly(ethylene glycol) diacrylate (PEGDA) as a crosslinker. On this basis, an interpenetrating polymer network structure (IPN) was obtained by introducing a second network of PEGDA-crosslinked poly(N-isopropylacrylamide). Multicomponent networks obtained were characterized by FTIR, TGA, and swelling kinetics in different solvents. Both CPN and IPN showed a high swelling degree in aqueous media (up to 1800 and 1200%, respectively), reaching the equilibrium swelling within 24 h. Additionally, IPN showed temperature-responsive swelling in an aqueous solution as the equilibrium swelling degree decreased considerably with an increase in the temperature. In order to evaluate the networks' potential as drug carriers, swelling in DSP aqueous solutions of varied concentration was investigated. It was established that the amount of encapsulated DSP could be easily controlled by the concentration of drug aqueous solution. In vitro DSP release was studied in buffer solution (BS) with pH 7.4 at 37 °C. The results obtained during DSP loading and release experiments proved the feasibility of the developed multicomponent hydrophilic polymer networks as effective platforms for potential dermal application.

Nano-dispersed yttria-stabilized zirconia powder: Phase, morphology, and conductivity investigation with different chelating agents via a modified sol-gel method

8 mol% yttria-stabilized zirconia nano-powders were synthesized via a novel sol–gel method employing basic zirconium carbonate, acetic acid, and different chelating agents (citric acid, oxalic acid, and ethylenediaminetetraacetic acid (EDTA)). The dried gel and calcined nano-powders were characterized using various techniques to investigate their thermal behavior, phase composition, particle size, microstructure morphology, and electrochemical performance. It was found that the dried gel had different polymeric network structures based on the different molecular structures, number of functional groups, and acidity of the chelating agents, which led to different properties after calcination. The smallest particle size, best dispersion, and narrowest grain size distribution were obtained for the EDTA sample after calcination at 600 °C, which are attributed to the unique functional groups in EDTA. The highest relative density and smallest grain size of the EDTA sample, which resulted in enhanced grain boundary contribution and effective conducting area, led to increased ionic conductivity (0.06 S cm−1).

Ultrasonic/electrical dual stimulation response nanocomposite bioelectret for controlled precision drug release

Electret materials have attracted extensive attention because of their permanent polarization and electrostatic effect. However, it is one of problem that needs to be solved in biological application to manipulate the change of surface charge of electret by external stimulation. In this work, a drug-loaded electret with flexibility and no cytotoxicity was prepared under relatively mild conditions. The electret can release the charge through stress change and ultrasonic stimulation, and the drug release can be accurately controlled with the help of ultrasonic and electric double stimulation response. Here, the dipoles like particles of carnauba wax nanoparticles (nCW) are fixed in the matrix based on the interpenetrating polymer network structure, and "frozen" oriented dipolar particles that are treated by thermal polarization and cooled at high field strength. Subsequently, the charge density of the prepared composite electret can reach 101.1​nC/m2 at the initial stage of polarization and 21.1​nC/m2 after 3 weeks. In addition, the stimulated change of electret surface charge flow under cyclic tensile stress and cyclic compressive stress can generate a current of 0.187​nA and 0.105​nA at most. The ultrasonic stimulation results show that when the ultrasonic emission power was 90% (Pmax​=​1200​W), the current of 0.472​nA can be generated. Finally, the drug release characteristics and biocompatibility of the nCW composite electret containing curcumin were tested. The results showed that it not only had the ability to accurately control the release by ultrasound, but also triggered the electrical effect of the material. The prepared drug loaded composite bioelectret provides a new way for the construction, design and testing of the bioelectret. Its ultrasonic and electrical double stimulation response can be accurately controlled and released as required, and it has broad application prospects.