Regenerative antibacterial hydrogels from medicinal molecule for diabetic wound repair.

Hydrogel products for chronic diabetic wounds, a serious and prevalent complication of diabetes, show limited effects on disability and remain nonspecific. Thus, improvements in the usage of pharmaceutical molecule in the hydrogels are highly desirable to increase the therapeutic effect of hydrogels. In this study, thioctic acid (a common medicine molecule in diabetes treatment) is used for preparing regenerative antibacterial hydrogels (RAH) which contains in situ synthesized silver nanoparticles (AgNPs). The RAH shows regenerative, self-healing and injectable ability, because of the reversible hydrogen and coordination bonds. With good regenerative capacity, RAH can be stored as powder to avoid the water loss and facilitate storage availability. Owing to the antioxidant properties of thioctic acid, the RAH can decrease the oxidative damage and retain cell proliferation efficiency. Due to the in situ synthesized AgNPs, the RAH also exhibits extraordinary antimicrobial capacities against MDR bacteria. All of these superiorities enable RAH to be a promising therapy for chronic diabetic wounds.

Wide-Temperature Flexible Supercapacitor from an Organohydrogel Electrolyte and Its Combined Electrode.

Hydrogel-based flexible supercapacitors possess the merits of highly ionic conductivity and superior power density, but the existence of water limits their application in extreme temperature scenarios. Noticeably, it is a challenge for people to design more extremely temperature adaptable systems for flexible supercapacitors based on hydrogels with a wide temperature region. In this work, a wide-temperature flexible supercapacitor that can operate at -20-80 °C was fabricated by an organohydrogel electrolyte and its combined electrode (also known as an electrode/electrolyte composite). Upon introducing highly hydratable LiCl into an ethylene glycol (EG)/H2 O binary solvent, owing to the ionic hydration effect of LiCl and the hydrogen bond interaction between EG and H2 O molecules, the organohydrogel electrolyte exhibits satisfactory resistance to freezing (freezing point of -113.9 °C), anti-drying capability (78.2 % of weight retention after vacuum drying at 60 °C for 12 h) and excellent ionic conductivity both at room temperature (13.9 mS cm-1 ) and low temperature (6.5 mS cm-1 after 31 days at -20 °C). By using organohydrogel electrolyte as binder, the prepared electrode/electrolyte composite effectively reduces interface impedance and enhances specific capacitance due to the uninterrupted ion transport channels and extended interface contact area. The assembled supercapacitor delivers a specific capacitance of 149 F g-1 , a power density of 160 W kg-1 , and an energy density of 13.24 Wh kg-1 at a current density of 0.2 A g-1 . The initial 100 % capacitance can be maintained after 2000 cycles at 1.0 A g-1 . More importantly, the specific capacitances can be well maintained even at -20 and 80 °C. With other advantages such as excellent mechanical property, the supercapacitor is an ideal power source suitable for various working conditions.

Extreme-environment-adapted eutectogel mediated by heterostructure for epidermic sensor and underwater communication.

In recent years, gel-based ion conductor has been widely considered in wearable electronics because of the favorable flexibility and conductivity. However, it is of vital importance, yet rather challenging to adapt the gel for underwater and dry conditions. Herein, an anti-swelling and anti-drying, intrinsic conductor eutectogel is designed via a one-step radical polymerization of acrylic acid and 2, 2, 2­trifluoroethyl methacrylate in binary deep eutectic solvents (DESs) medium. On the one hand, the synergistic effects of hydrophilic/hydrophobic heteronetworks can elicit the integrity stability of eutectogel in liquid environment. It is proved that both the mechanical property and conductivity are maintained after immersing in different salt, alkaline and acid solution and organic solvent for one month. On the other hand, the eutectogel inherits well conductivity (93 mS/m), anti-drying and antibacterial properties from DESs. Based on the above features, the resulting eutectogel can be assembled as smart sensor for stable information transmission in air and underwater with fast response time (1 s), high sensitivity (Gauge factor = 1.991) and long-time reproducibility (500 cycles, 70 % strain). Considering the simple preparation and integration of multiple functions, the binary cooperative complementary principle can provide insights into the development of next-generation conductive soft materials.

Hydrogels as the plant culture substrates: A review.

A class of hydrophilic polymers known as "hydrogels" have extensive water content and three-dimensional crosslinked networks. Since the old period, they have been utilized as plant culture substrates to get around the drawbacks of hydroponics and soil. Numerous hydrogels, particularly polysaccharides with exceptional stability, high clarity, and low cost can be employed as plant substrates. Although numerous novel and functionalized hydrogels might assist in overcoming the drawbacks of conventional media and giving them more functions, the existing hydrogel-based plant growth substrates rarely benefit from the developments of gels in the previous few decades. Prospects include the development of new conduction techniques, the creation of potential new hydrogels, and the functionalization of the hydrogel as plant culture substrates.

"Water-in-Deep Eutectic Solvent" Gel Electrolytes Synergistically Controlled by Solvation Regulation and Gelation Strategies for Flexible Electronic Devices.

Recent developments in flexible electronics have heightened the need for electrolytes with high safety, ionic conductivity, and electrochemical stability. However, neither conventional organic electrolytes nor aqueous electrolytes can meet the above requirements simultaneously. Herein, a novel "water-in-deep eutectic solvent" gel (WIDG) electrolyte synergistically controlled by the solvation regulation and gelation strategies is reported. The water molecules introduced into deep eutectic solvent (DES) participate in the solvation structure regulation of Li+, thus endowing the WIDG electrolyte with high safety, thermal stability, and outstanding electrochemical performance, including high ionic conductivity (∼1.23 mS cm-1) and a wide electrochemical window (∼5.4 V). Besides, the polymer in the gel interacts with DES and H2O, further optimizing the electrolyte with excellent mechanical strength and higher operating voltage. Benefiting from these advantages, the lithium-ion capacitor constructed by WIDG electrolyte presents a high areal capacitance of 246 mF cm-2 with an energy density of 87.3 µWh cm-2. The use of the gel enhances the electrode structure stability, resulting in desirable cycling stability (>90% capacity retention after 1400 cycles). Moreover, the WIDG-assembled sensor exhibits high sensitivity and rapid real-time detection of motion. This work will provide guidelines for designing high-safety and high-operating-voltage electrolytes for flexible electronics.

Oxidation stability enhanced MXene-based porous materials derived from water-in-ionic liquid Pickering emulsions for wearable piezoresistive sensor and oil/water separation applications.

HYPOTHESIS: Stemming from their unique superiorities, Ti3C2-MXenes have emerged as versatile 2D materials for a myriad of appealing applications. However, two crucial issues are detrimental to maximize the inherent properties of MXenes for further specific developments, i.e. restacking problem and environmental instability. EXPERIMENTS: Herein, we develop an effective strategy, constructing water-in-ionic liquid (W/IL) Pickering emulsions with further polymerization of the continuous phase, to fabricate oxidation stability enhanced Ti3C2-MXene based porous materials. It is the first time to utilize a brand new platform between the immiscible IL and water for MXene nanosheets to assemble with guest species serving as building blocks for macromonoliths. FINDINGS: The prepared porous materials can provide elastic hollow-sphere structures derived from emulsion template, for wearable piezoresistive sensor with high sensitivity, excellent accuracy and favorable reproducibility. Intriguingly, ILs as dispersion and surface modification with polymeric ionic liquids (PILs) play indispensable roles in ameliorating oxidation stability of MXenes in porous materials, by virtue of quenching reactive oxygen species (ROS) and forming protective layer through the capping effect. Furthermore, the processed aerogels after supercritical drying can selectively absorb several organic solvents owing to their high hydrophobicity, abundant porosity and sufficient mechanical strength. All results indicate that the innovative strategy can simultaneously circumvent two major drawbacks of MXenes for the first time, and shed light on the opportunity to further enrich their practical applications by constructing multifunctional platform.

Ultra-Sensitive and Ultra-Stretchable Strain Sensors Based on Emulsion Gels with Broad Operating Temperature.

Hydrogels with mechanical elasticity and conductivity are ideal materials in wearable devices. However, traditional hydrogels are fragile upon mechanical loading and lose functions in climate change because the internal water undergoes freeze and dehydration. Herein, we synthesize stable emulsions at high and low temperatures by introducing glycerol into the W/W emulsions. Then the high-stable emulsions are used as templates to produce the freestanding emulsion gels with enhanced mechanical strength and conductivity. The introduction of glycerol endows emulsions and emulsion gels with high and low temperature resistance (-20 to 90 °C). The fabricated strain sensors based on emulsion gels show high sensitivity (gauge factor=6.240), high stretchability (1081 %), fatigue resistance, self-healing and adhesion properties, realizing the repeatable and accurate detection of various human motions. These high-performance and eco-friendly emulsion gels can be promising candidates for next-generation artificial skin and human-machine interface.

Antiswelling and Durable Adhesion Biodegradable Hydrogels for Tissue Repairs and Strain Sensors.

Adhesive hydrogels have gained great interest for biomedical applications, because of their great adhesion, tunable structure, high water content, and biocompatibility. However, it is still challenging to engineer hydrogel materials combining tissue repairs and strain sensors. In this work, poly(thioctic acid) (PTA) is used as a skeleton structure and mixed with polydopamine (PDA), resulting in hydrogels with excellent stretchability, resilience, and adhesion, which can adhere to various organic (porcine skin) and inorganic materials (ceramic, wood, glass, etc.) in both dry and wet environments. The hydrogels also exhibit antiswelling behavior, self-healing, and repeatable adhesion capacity (seven times), which are meaningful for bioapplications and show satisfactory biocompatibility, biodegradation, cell affinity, and ability to limit apoptosis in both in vitro and in vivo experiments. In the full-thickness skin defect model, the hydrogels can accelerate the wound healing process. The introduction of Fe3+ can significantly enhance the conductivity of the hydrogels, making it possible for the hydrogels to be used as strain sensors. This functional hydrogel may find an appealing application as an antiswelling and durability adhesive for strain sensors.

Ionic-surfactants-based thermotropic liquid crystals.

Thermotropic liquid crystals (TLCs) are a series of soft materials with ordered arrangements of repeating structural units in a certain range of temperature. Specifically, the TLCs constructed by the electrostatic combination between ionic surfactants and other oppositely charged groups have received great attention in the field of optoelectronic devices, material transportation and separation, smart materials as well as biosensing. As typical amphiphilic molecules, ionic surfactants with charged head-groups and long alkyl tails exhibit unique self-assembly behaviors, being preferable as flexible building blocks of TLCs. In this review, we have discussed the TLCs formed by salt-free catanionic surfactants and ionic surfactants with other functional groups, including metal ions, nanoclusters, biomolecules, and polyelectrolytes. The design of such TLC molecules, the influencing factors of the mesophases, and the related applications of the TLCs are discussed in detail. Because of their easy preparation and variable structure, these TLCs are expected to greatly widen the application scope of the relevant functional molecules. At the end of this review, we put forward some ideas with regard to the aspects that are required to be improved and propose the possible development trend in this direction. It is expected that through this review, the important roles of ionic surfactants in building TLCs will be highlighted and thus, more studies will be inspired to exploit more TLCs based on ionic surfactants with excellent properties.

Functional polyaspartic acid derivatives as eco-friendly corrosion inhibitors for mild steel in 0.5 M H2SO4 solution.

To improve the corrosion inhibition efficiency of eco-friendly polyaspartic acid (PASP) for mild steel in acidic solutions, PASP/N-(3-aminopropyl)imidazole (PD-1) and PASP/N-(3-aminopropyl)-imidazole-co-n-dodecylamine (PD-2) were chemically synthesized by the facile ring-opening reaction of polysuccinimide. Inhibition efficiencies of PD-1 and PD-2 for mild steel in a 0.5 M H2SO4 solution were investigated by electrochemical measurements (electrochemical impedance and polarization) and the weight loss method. In comparison with PASP, PD-1 and PD-2 show improved inhibition efficiencies due to the functional groups. In particular, PD-2 shows superior corrosion inhibition capacity, and the efficiency is up to 94% at a relatively low concentration of 100 mg L-1 at 298 K, as determined by potentiodynamic polarization measurements. Surface analysis of mild steel with PD-2 as an inhibitor clearly indicates that the inhibitor molecules adsorb on the steel surface and efficiently inhibit the corrosion of mild steel. The present work provides very meaningful results in designing and preparing new polymer inhibitors with high inhibition efficiency.