Temperature-sensitive and solvent-resistance hydrogel sensor for ambulatory signal acquisition in“moist/hot environment”

To realize continuously and stably work in a“moist/hot environment”,flexible electronics with excellent humid resistance,antiswelling,and detection sensitivity are demanding.Herein,a solvent-resistant and temperature-ultrasensitive hydrogel sensor was prepared by combining MXene and quaternized chitosan(QCS)with the binary polymer chain.The strong electrostatic interaction between the QCS chain and the poly(acrylic acid)(PAA)network endows the hydrogel stability against solvent erosion,high temperature,and high humidity.The strong dynamic interaction between MXene and polymer matrix significantly improves the mechanical properties and sensing(strain and temperature)sensitivity of the hydrogel.The hydrogel strain sensor exhibits a high gauge factor(5.53),temperature/humidity tolerance(equilibrium swelling ratio of 2.5%at 80℃),and excellent cycle stability,which could achieve a remote and accurate perception of complex human motion and environment fluctuation under aquatic conditions.Moreover,the hydrogel sensor exhibits impressive thermal response sensitivity(-3.183%/℃),ultrashort response time(<2.53 s),and a low detection limit(<0.5℃)in a wide temperature range,which is applied as an indicator of the body surface and ambient temperature.In short,this study broadens the application scenarios of hydrogels in persistent extreme thermal and wet environments.

Polymer-based membranes for solvent-resistant nanofiltration:A review

Separation of organic mixture is an inevitable process in most modern industrial processes. In the quest for a more sustainable and efficient separation, solvent-resistant nanofiltration(SRNF) has emerged as a promising answer. This is because SRNF is a membrane-based process which offers the key advantages of high efficacy and low energy intensity separation. In particular, polymer-based membranes can offer compelling opportunities for SRNF with unprecedented cost-effectiveness. As a result, intensive research efforts have been devoted into developing novel polymer-based membranes with solvent-resistant capacities as well as exploring potential applications in different types of industries. In this review, we aim to give an overview of the recent progress in the development of the state-of-the-art polymer-based membranes for SRNF in the first section. Emerging nanomaterials for mixed matrix and thin film nanocomposite membranes are also covered in this section. This is followed by a discussion on the current status of membrane engineering and SRNF membrane commercialization. In the third section, we highlight recent efforts in adopting SRNF for relevant industrial applications such as food, bio-refinery, petrochemical, fine chemical and pharmaceutical industries followed by separations of enantiomers in stereochemistry, homogeneous catalysis and ionic liquids. Finally, we offer a perspective and provide deeper insights to help shape future research direction in this very important field of SRNF.

Fabrication of Solvent-Resistant Nanofiltration Membrane via Interfacial Polymerization Based on Cellulose Acetate Membrane

Although a great progress has been achieved for the development of NF membranes and technologies and SRNF do show a great potential in the separation of organic components, an NF membrane with good separation performance and good resistance to organic solvents are urgently needed for a more complicated situation in practical. In this study, a kind of solvent-resistant nanofiltration (SRNF) membrane was fabricated via interfacial polymerization on a laboratory optimized cellulose acetate (CA) basic membrane. The effects of interfacial polymerization parameters, such as water phase concentration, immersed time in the water phase and in the organic phase, on the pure water flux and rejection rate of C-2R yellow dyestuffs were investigated. A highest dye rejection rate of 72.9% could be obtained by water phase solution containing 1% m-xylylenediamine (mXDA) and organic phase solution with 0.2% trimesoyl chloride (TMC) under immersed time in water phase of 6 minutes and in organic phase of 40 seconds. This membrane demonstrated better resistance to methyl alcohol compared to commercial membrane. This study may offer an avenue to develop a solvent-resistant nanofiltration membrane.

CHARACTERIZATION OF REGENERATED CELLULOSE MEMBRANES HYDROLYZED FROM CELLULOSE ACETATE

A series of cellulose acetate membranes were prepared by using formamide as additive, and then were hydrolyzed in 4 wt% aqueous NaOH solution for 8 h to obtain regenerated cellulose membranes. The dependence of degree of substitution, structure, porous properties, solubility and thermal stability on hydrolysis time was studied by chemical titration, Fourier transform infrared spectroscopy, scanning electron microscopy, wide-angle X-ray diffraction, and differential scanning calorimetry, respectively. The results indicated that the pore size of the regenerated cellulose membranes was slightly smaller than that of cellulose acetate membrane, while solvent-resistance, crystallinity and thermostability were significantly improved. This work provides a simple way to prepare the porous cellulose membranes, which not only kept the good pore characteristics of cellulose acetate membranes, but also possessed solvent-resistance, high crystallinity and thermostability. Therefore, the application range of cellulose acetate membranes can be expanded.

Solvent-resistant porous membranes using poly(ether−ether ketone): preparation and application

Poly(ether−ether ketone)(PEEK)is a linear aromatic macromolecule,which can form semi-crystalline aggregative status,allowing PEEK materials to have strong environment tolerance and excellent physicochemical properties.PEEK materials have become a promising alternative to fabricate particular membranes used in extreme conditions.In the past few decades,many researches and evolutions have emerged in membrane fabrication with PEEK materials and its applications for treating organic solvents and their mixtures;however,there are little systematic and comprehensive literature to summarize fabrication approaches,compile applications,and elaborate PEEK property-structure relationship.In this review,the main approaches to fabricate PEEK-based membranes are illustrated concretely,including conventional thermal-induced and non-solvent-induced phase separation,and novel chemical-induced crystallization;the representative applications in ultrafiltration,nanofiltration and membrane contactor containing organic solvents are demonstrated systematically.Meanwhile,the mechanism to tune PEEK solubility in solvents,which can be achieved by altering monomers in synthesis processes or changing membrane preparation routes,is deeply analyzed.Moreover,the existing problems and the future prospects are also discussed.This review provides positive guidance for designing and fabricating membranes using PEEK and its derivative materials for task-specific applications in harsh conditions.

High-performance all-solution-processed inverted quantum dot light-emitting diodes enabled by water treatment

All-solution-processed inverted quantum dot(QD)light-emitting diodes(QLEDs)with transparent bottom cathodes can be directly connected to the n-type thin-film transistors,offering a feasible solution for low-cost active matrix-driven QD displays.However,the subsequent solution-deposition of the hole-transporting layer destroys the underneath QD films,resulting in largely deteriorated device performance.Various strategies have been implemented to prevent QD film from dissolution,but all at a heavy cost of device performance suffering from either reduced efficiency or increased driving voltage.Here,a facile and effective water-treatment approach for QD film to fabricate inverted QLEDs through all solution processing is reported.The water treatment substitutes the long-chain oleate ligands with hydroxyl groups,resulting in significantly improved non-polar solvent resistance of the QD films.Importantly,the QD films reserve their excellent photoluminescence efficiency after water treatment.With the water-treated QD film as the emissive layer,all-solution-processed inverted red QLED with a peak external quantum efficiency of 19.6%,a turn-on voltage of 1.8 V,and a T50 operational lifetime of 150,000 h at 100 cd·m^(-2) was achieved.Furthermore,efficient and low-voltage-driven green and blue QLEDs can also be prepared with this method.This work provides a feasible strategy for the fabrication of high-performance all-solution-processed inverted QLEDs,paving the way toward achieving QLEDs by all ink-jet printing.