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Tough, anti-drying, thermoplastic, and biodegradable hydrogels was developed and successfully applied as a wide linear range and fast response strain sensor.

Conductive hydrogels crosslinked by charge-transfer complexes are prepared and fabricated as strain and temperature sensors with high sensitivity. The hydrogel-based sensors can retain good sensing performance after the thermoplastic process.

Hydrogel strain sensors with extreme temperature tolerance have recently gained great attention. However, the sensing ability of these hydrogel strain sensors changes with temperature, resulting in the variety of output signals that causes signal distortion. In this study, double-network hydrogels comprising SiO

In recent years, flexible strain sensors have attracted increasing interest, and accurate sensing and comfortable wearables are highly demanded. However, current flexible strain sensors fail to have wide linearity and...

This paper investigated ultraviolet A light-emitting diode (UVA-LED) irradiation to activate Fe(VI) for the degradation of micropollutants (e.g., sulfamethoxazole (SMX), enrofloxacin, and trimethoprim). UVA-LED/Fe(VI) could significantly promote the degradation of micropollutants, with rates that were 2.6-7.2-fold faster than for Fe(VI) alone. Comparatively, UVA-LED alone hardly degraded selected micropollutants. The degradation performance was further evaluated in SMX degradation via different wavelengths (365-405 nm), light intensity, and pH. Increased wavelengths led to linearly decreased SMX degradation rates because Fe(VI) has a lower molar absorption coefficient at higher wavelengths. Higher light intensity caused faster SMX degradation, owing to the enhanced level of reactive species by stronger photolysis of Fe(VI). Significantly, SMX degradation was gradually suppressed from pH 7.0 to 9.0 due to the changing speciation of Fe(VI). Scavenging and probing experiments for identifying oxidative species indicated that high-valent iron species (Fe(V)/Fe(IV)) were responsible for the enhanced degradation. A kinetic model involving target compound (TC) degradation by Fe(VI), Fe(V), and Fe(IV) was employed to fit the TC degradation kinetics by UVA-LED/Fe(VI). The fitted results revealed that Fe(IV) and Fe(V) primarily contributed to TC degradation in this system. In addition, transformation products of SMX degradation by Fe(VI) and UVA-LED/Fe(VI) were identified and the possible pathways included hydroxylation, self-coupling, bond cleavage, and oxidation reactions. Removal of SMX in real water also showed remarkable promotion by UVA-LED/Fe(VI). Overall, these findings could shed light on the understanding and application of UVA-LED/Fe(VI) for eliminating micropollutants in water treatments.

UV-curable coatings have been receiving more and more attention for their high performance and environmentally friendly advantages, which meet the “5 E” requirements of coating development. Vinyl oligomer is the main factor affecting the performance of UV-curable coating, but it is difficult to meet the requirements of high-end UV curing technology due to its high viscosity, low vinyl functionality, and high cost. Herein, polyesters with lateral double bonds were prepared by ring-opening polymerization of acid anhydride and glycidyl methacrylate. The epoxy compound without vinyl groups was used to participate in the polymerization reaction to adjust the viscosity and vinyl functionality of the resin. Furthermore, the molecular structure and molecular weight of the polyesters were characterized by FTIR, 1H NMR, and GPC. The effects of the categories and proportions of acid anhydride and glycidyl ether on the viscosity and hardness of the coating films were studied. The results indicated that the use of acid anhydrides containing phenyl rigid groups could significantly increase the hardness of the paint film, and the long-chain tertiary glycidyl carbonate (E10P) had the best viscosity reduction effect. When the molar ratio of acid anhydride, GMA and E10P was 4:1:3, the viscosity of the prepared vinyl polyester was low to 2755 mPa·s. In this case, the hardness of the paint film was as high as H, and it also exhibited excellent water resistance and alcohol resistance.

Natural and artificial restoration measures are widely used to restore degraded ecosystems, such as degraded alpine meadow. The objective of this research was to evaluate the advantages and disadvantages of natural and artificial measures for extremely degraded alpine meadows. We removed the surface soil (0–10 cm) of the alpine meadow to simulate the extremely degraded “black soil beach,” and set artificial measures (planting Festuca sinensis (E) and Elymus sibircus L. cv. chuan-cao No. 1 (F)) and natural recovery (N) (without any artificial auxiliary measures) in the northeastern part of the Qinghai-Tibet Plateau (QTP), China. After 3 years, we determined the characteristics of community and soil in the artificial and natural treatment. The results show that the species number, above-and below-ground biomass (AB, BB), root-shoot ratio (R/S) in N is significantly higher than that in artificial restoration (E and F); while the community coverage and concentration of soil total carbon, total nitrogen, microbial biomass carbon, microbial biomass nitrogen and microbial biomass phosphorus (TC, TN, MBC, MBN and MBP) in artificial restoration is significantly higher than that in N. In conclusion, compared with N, artificial measures (E and F) are not completely beneficial to the development of plant community diversity and the restoration of soil nutrients in the extremely degraded meadow. Thus, the establishment of artificial grassland is not necessarily better than natural recovery for the extremely degraded alpine meadow.

As the laws about emission of volatile organic compounds (VOCs) become more and more stringent, low VOC content coatings, such as high solid polyurethane coating, gradually attract great attention. Herein, a series of star-shaped hydroxyl polyesters (SHPs) were synthesized by methyl hexahydrophthalic anhydride (MHHPA), diisopropanolamine (DIPA), and monoglycidyl ether. The number of their average molecular weights is ranged from 913 to 1390 with 1.55–1.75 of PDI. The viscosities of SHPs are low to 1060 mPa·s. The molecular structures of SHPs were characterized by Fourier transform infrared (FTIR) and 1H nuclear magnetic resonance (1H NMR) spectroscopies. The high-solid two-component polyurethane coatings (2 K-PU) from SHP-3 have a 65% of the solid contents and exhibit 20 mPa·s of the applied viscosity with 310 g/L of VOC contents. Moreover, the polyurethane film displays high coating hardness up to 2H, as well as excellent chemical resistance and good thermal stability.

A series of N-alkylated aminosulfonic acids (NASAs) were synthesized with 1,4-butane sultone and primary amines and then reacted with hexamethylene diisocyanate trimer to obtain water-dispersible polyisocyanates (WDPs). Two-component waterborne polyurethane (2K-WPU) coatings were finally prepared by the reaction of WDPs and aqueous hydroxyl resins. The structures and properties of WDPs and 2K-WPU coatings were characterized. The effects of the categories and amounts of NASAs on the properties of WDPs and 2K-WPU coatings, including viscosities, water resistance and transparency, were investigated. The results showed that the average molecular weights and viscosities of the WDPs increased with the increase in the amounts and molecular weights of NASAs. 3-(Cyclohexylamino)-1-propanesulfonic acid possesses a high molecular weight, resulting in low-concentration –SO3 per mass, so a high concentration up to 3.5 wt% was needed to meet water-dispersible requirements. On the other hand, 3-isobutylamino-1-propanesulfonic acid (IBAPS) has high-concentration –SO3 per mass and only a low concentration (2.5 wt%) was required to offer satisfactory water dispersibility. 2K-WPU film cured by IBAPS-WDP displayed high gloss, good transparency and excellent water resistance owing to suitable steric hindrance and high content of –SO3H per mass.

To improve the chemical resistance of non-isocyanate polyurethane (NIPU), two kinds of diglycidyl ether, bisphenol AF (E-AF) and perfluorooctyl glycidyl ether (PFGE), were selected to synthesize two different cyclic carbonates, bisphenol AF (EC-AF) and perfluorooctyl cyclic carbonate (PFGC), respectively. These cyclic carbonates were successfully used to prepare fluorine-containing non-isocyanate polyurethane coatings. The effects of PFGC amounts on the properties of NIPU were studied, and it was found that the contact angles of water, diiodomethane, and hexadecane were increased with the addition of PFGC and up to 106.7°, 80.2°, and 72.7°, respectively, whereas the pendulum hardness of NIPU coatings relatively decreased with the increase in PFGC contents. The NIPU coatings exhibited excellent flexibility, adhesion, and impact resistance. They also displayed good thermal stability with 5% weight loss temperature (T5%) ranging from 249 to 271°C. Moreover, these coatings possessed very low water uptake, excellent hydrophobic/oleophobic properties, and corrosion resistance properties.

Non-isocyanate polyurethane (NIPU) synthesized by cyclic carbonate resins (CC) and amines satisfies the growing awareness of environmental protection and attracts increasing research interest. However, CC are often prepared by CO2 and epoxy resin under high temperature and high pressure for a satisfactory conversion rate. This preparation process not only requires special equipment, but also causes the high cost of CC. To promote the synthesized method of CC, herein, we reported the successfully preparation of CC under atmosphere pressure with excellent properties. O-chloro alcohol resins were first synthesized by polyol reacted with anhydride and epichlorohydrin (ECH). This resins then reacted with sodium bicarbonate (NaHCO3) to offer CC under atmospheric pressure. The structures of CC were characterized by FTIR and 1H NMR. The NIPU were prepared with CC and amines at different molar ratios. It was found that the NIPU films exhibited high hardness up to 2H as well as good adhesion. It also has excellent thermal stability with the initial thermal decomposition temperature up to 260 °C (the molar ratio of CC: isophorone diamine (IPDA) = 1:1). To further improve the chemical resistance of NIPU film, the NIPU was modified with epoxy resins. We found that the NIPU film with 40 wt% of E-20 exhibited excellent chemical resistance. Surprisingly, this NIPU film also displayed excellent flexibility and good impact resistance (100 cm.kg).

Benzothiazole (BZA) and benzotriazole (BTZ) as emerging contaminants were found persistent in aquatic environments and toxic to aquatic organisms. The degradation of BZA and BTZ by UV/chlorine was systematically investigated in this study, and the results showed that BZA and BTZ can be remarkably removed by UV/chlorine compared with UV alone and dark chlorination. The radical quenching tests showed that degradation of BZA and BTZ by UV/chlorine involved the participation of reactive chlorine species (RCS), hydroxyl radical (HO·), and UV photolysis. HO· dominated BZA degradation at neutral and alkalinity, while RCS dominated BTZ degradation. The second-rate order constants for ClO· and BZA and BTZ were 2.22 × 108 M−1 s−1, and 2.40 × 108 M−1 s−1, respectively. Besides, the second-order rate constants for HO· and BZA and BTZ were also determined at pH 5.0, 7.0, and 9.0, respectively. The degradation efficiency of BZA by UV/chlorine was substantially promoted at acidic conditions, while the degradation efficiency of BTZ was promoted at both acidic and specific alkaline range mainly due to the reactivity of radical species and deprotonated form. The influence of Cl− was negligible, but the suppression effect of humic acid was slight during the BZA and BZT degradation by UV/chlorine. The transformation products were detected and the possible pathways were proposed. Seven disinfection by-products (DBPs) were identified both in BZA and BTZ degradation and trichloromethane was the main DBP. The toxicity assessment performed by luminescent bacteria and ECOSAR analysis indicated that the detoxification of BZA could be achieved by UV/chlorine, whereas the toxicity of BTZ was increased mainly due to the formation of intermediates. The findings from this study demonstrated UV/chlorine is likewise efficient for BZA and BTZ removal but the toxicity should be considered in the BTZ degradation.

In this study, the effective removal of organoarsenic by the combined process of "chlorination + Fe(II)" was achieved. Chlorine could effectively degrade roxarsone (ROX) over pH from 5 to 10. The fitting results of acid-base protonation model proved that the degradation of ROX was mainly attributed to the reaction of HOCl and deprotonated ROX. The transformation of arsenic species conformed to the fitting results of two-channel kinetic model, in which 32.4% of ROX was oxidized to As(V) via electron transfer pathway (ii) and the rest was converted into monochloro-ROX via electrophilic substitution pathway (i). Humic acid inhibited the degradation of ROX due to the competitive consumption of chlorine and the restraint on the pathway ii. Subsequently, an enhanced removal of total arsenic achieved after chlorination, due to that the generating As(V) and monochloro-ROX were easier adsorbed compared with ROX, over 97.8% of total arsenic was removed by ferric (oxyhydr)oxides which in-situ formed from the oxidation of Fe(II). Additionally, toxicity studies indicated that the acute toxicity was significantly eliminated by adding Fe(II) after chlorination, likely due to the removal of As(V) and chlorinated products. Furthermore, organoarsenic was also effectively removed by the combined process of "chlorination + Fe(II)" in real water.

The cyclic carbonate derivatives carrying carboxyl groups were prepared via the reaction of the sorbitol-based cyclic carbonate (SC) with anhydrides including succinic anhydride, o-phthalic anhydride, and maleic anhydride. (Succinic anhydride-, o-phthalic anhydride-, and maleic anhydride-based cyclic carbonates were named SSC, PSC, and MSC, respectively.) The structures of SC, SSC, PSC, and MSC were characterized by 1H NMR and FTIR. Then, the novel sorbitol-based aqueous cyclic carbonate dispersion was prepared. It was found that SSC dispersion possessed excellent stability and its particle sizes ranged from 63 to 174 nm with −73.3 to −48.2 mV for the zeta potentials. A series of novel waterborne nonisocyanate polyurethanes coatings (WNIPU) were successfully prepared by sorbitol-based cyclic carbonate reacted with diamines. The effects of diamine categories and the molar ratios of isophorone diamine (IPDA) and hexamethylene diamine (HMDA) on the properties of WNIPU were studied. The results showed that the pencil and pendulum hardness of WNIPU coatings were all relatively decreased with the increase in HMDA contents. The WNIPU coatings exhibited excellent flexibility, adhesion, gloss, and impact resistance with the molar ratios of IPDA/HMDA ranging from 1:1 to 1:3. Moreover, cured films display good thermal stabilities with only 5% weight loss (T5%) in temperatures ranging from 246 to 272°C.

We reported here a new platform of supramolecular hydrogels cross-linked by the cooperation of metal–ligand coordination and hydrophobic interaction. A salicylaldehyde benzoyl hydrazone-terminal poly(ethylene glycol) (2SBH-PEG) was synthesized and formed small micelles in an aqueous environment. Addition of Ni2+ connected the low-molecular-weight 2SBH-PEG into a metallopolymer via metal–ligand coordination and led to micelle aggregation, resulting in gelation due to the enhancement of hydrophobic interaction. The forming hydrogel, Ni–PEGel, exhibited rapid self-healing ability and reversible pH-responsive property. Because of the containing metal coordination bond, it was also sensitive to the strong competing ligands, such as ethylenediaminetetraacetic acid (EDTA) and pyridine. In addition, Ni–PEGel showed colorimetric changes when exposed to biogenic amine (BA) vapor. The color development of Ni–PEGel toward BAs makes it a good candidate in monitoring food spoilage.

Stimuli-responsive materials activated by a pair of molecular or ionic species are of interest in the design of chemical logic gates and signal amplification schemes. There are relatively few materials whose coactivated response has been well-characterized. Here, we demonstrate a specific ion coactivation (SICA) effect at the interfaces of transient polymer solids and liquid solutions. We found that depolymerization of the transient polymer, cyclic poly(phthalaldehyde) (cPPA), exhibited a SICA effect when the cPPA core-shell microcapsules were suspended in ion-containing acidic methanol solutions. Significant acceleration in cPPA depolymerization rate is triggered by the combination of acid and ion coactivators. Intriguingly, the SICA effect is related to the Hofmeister behavior. The SICA effect is primarily determined by anions, and cations exhibit a secondary effect that modulates the coactivation strength. Based on these observations, we developed cPPA programmable microcapsules whose payload release rates depend on the composition and concentration of the salt/acidic-methanol solutions.

Metallo-supramolecular hydrogels (MSH) with hydrophobic ligands were fabricated by a simple but versatile strategy. This strategy is expected to extend the selection of ligands in hydrogel systems and enables the forming hydrogels to have more attractive properties and applications. An amphiphilic polymer with a hydrophobic Schiff base ligand, poly(N,N-dimethylacrylamide-co-2-(benzylidene-hydrazonomethyl)-phenol) (P(DMA-co-BHMP)), was synthesized and self-assembled to micelles in aqueous solution. The addition of selected divalent metal ions (Cu2+, Co2+, Ca2+, Mn2+, Pb2+ and Fe2+) connected each micelle with metal–ligand coordination and resulted in gelation. The designed ligand with a pH sensitive Schiff base structure (BHMP) contributed to the pH-responsive properties of the prepared hydrogels. Rheological studies displayed that hydrogels crosslinked by Cu2+ (Cu-gel) were injectable and rapidly self-healing. The addition of competing ligands (EDTA and EDA) caused the degradation of Cu-gel. We also illuminated the reversible redox gel–sol transition of the hydrogel crosslinked by the resulting polymer and Fe2+ (Fe-gel). These self-healable and multi-stimuli responsive hydrogels have potential for biomedical and encapsulation–controlled release applications.

Aiming at the problem that the reported smart optical metallohydrogels were limited with poor mechanical properties, we reported here a novel smart optical metallohydrogel (Al-hydrogel) with excellent elongation, shape-memory ability, self-healing property, and controllable fluorescence intensity. The Al-hydrogel was obtained by the HHPMA-Al3+ and carboxylate-Al3+ coordination after one-pot micellar copolymerization of acrylic acid (AAc), acrylamide (AAm), and hydrophobic arylhydrazone-based ligand (HHPMA). This hydrogel was able to extend up to 5000% of its original length without fracture. Its emission intensity was tunable by OH-/H+ or Zn2+/AAc and increased by 500% with 0.1 M OH- or Zn2+. Its tunable fluorescence enabled us to repeatedly pattern it. A reversible system consisting of Fe3+/H+, was implemented to control the shape of the Al-hydrogel, endowing the Al-hydrogel with shape-memory ability. This highly stretchable and multifunctional Al-hydrogel has potential applications in information transmission, wearable devices, and flexible sensors.

With stimuli-responsive fluorescence and similar structure to extracellular matrix, smart fluorescent hydrogels are good candidate to encode data, especially in drug and food anti-counterfeiting. However, the development of these hydrogels in multistage information protection to achieve higher data security level is limited. Herein, multifunction smart fluorescent hydrogels were constructed and utilized to develop different multistage data encryption platforms. The hydrogels are a new type of fully physically cross-linked gelatin/metal complex associated poly(acrylamide-acrylate) double network gel. They displayed Fe3+ and H+-responsive fluorescence quenching, temperature or Fe3+-induced shape memory and self-healing properties. Combining the above abilities, several multistage data encryption platforms, from 2D to 3D data encryption, were designed. The results demonstrated a bright prospect for this smart fluorescent hydrogel in high security level anti-counterfeiting applications.

The design and development of macro-photoinitiators applicable to UV system has been attracted increasing attention for their excellent performance of low migration and high compatibility. Herein, four kinds of novel macro-photoinitiators (PI1-PI4) used in UV-curable coatings were synthesized by different isocyanates, 1-hydroxycyclohexyl phenyl ketone (Irgacure 184), 2-hydroxyethyl methacrylate (HEMA) and pentaerythritol triacrylate (PETA). The structures were analyzed by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). Moreover, the photopolymerization kinetics of the macro-photoinitiators were investigated by real-time FTIR. Results revealed that the macro-photoinitiators display higher curing efficiency, lower migration performance and better compatibility with formulation compositions compared to Irgacure 184. On the other hand, the macro-photoinitiators also served as self-initiating oligomers and had good thermal stability with 10 % weight loss temperatures (T10 %) above 299.7 °C. The UV-cured films consisting of oligomers and tripropylene glycol diacrylate (TPGDA) showed excellent physical properties and high curing efficiency and rapid curing rate.

Using organic coatings helps to protect PET (polyethylene terephthalates) surfaces, improve surface hardness, scratch resistance, and solvent resistance, prolong the service life of PET film, and to expand their scope of applications. There were some disadvantages, including poor flexibility and impact resistance in high-hardness coatings, organic coatings should also be modified to improve the toughness. Herein, a UV (ultraviolet curing) curable high-hardness organic coating used in PET surface protection was prepared and modified with inorganic nanoparticles, such as OVPOSS (octavinyl-polyhedral oligomeric silsesquioxane). The effects of the categories of nanoparticles on the coating performance were studied. UV-Vis spectra (ultraviolet visible light spectra), FT-IR (Fourier transform infrared spectrometer), TGA (thermogravimetric analysis), DMA (dynamic-mechanical), SEM (field emission scanning electron microscope), and AFM (atomic force microscope) were used to characterize the properties of the coatings. The results showed that the addition of eight-vinyl POSS to the organic coating significantly increased its glass transition temperature (Tg) from 100 to 120 &deg, C, improved its storage modulus from 167.6 MPa to 258.9 MPa, and raised its impact resistance and flexibility. The SEM and AFM images displayed that the eight-vinyl POSS particles were dispersed homogeneously in the coating, arranged in an ordered network, and had good compatibility with organic components. The film displayed excellent properties, including 4 H of the pencil hardness, 100 g cm of impact resistance, excellent flexibility, and 90% of light transmittance, with the addition of 0.3 wt % OVPOSS. TGA analysis revealed that the coating had good thermal stability, with 5% weight loss temperature up to 335 &deg, C.

Cyclic carbonates (TMC/PMDC/BTDC) were synthesized at atmospheric pressure by glycerine carbonate (GC) reacting with trimellitic anhydride (TMA) / pyromellitic anhydride (PMDA) / benzophenone-3,3′,4,4′-tetracarboxylicdianhydride (BTDA). 1H NMR spectra showed that the cyclic carbonates have 2.62, 3.72 and 3.43 cyclic carbonate functionality, respectively. TMC/PMDC/BTDC were further neutralized by dimethylethanolamine and dispersed in water to prepare TMC/PMDC/BTDC aqueous cyclic carbonate dispersion. They exhibited no stratification after 5000 r/min centrifugation for 60 min, indicating their good stability. The particle sizes of these dispersions ranged from 30 to 120 nm with the Zeta potential from -55 to -79.5 mV. A series of waterborne non-isocyanate polyurethane (T-WNIPU, P-WNIPU and B-WNIPU) coatings were successfully prepared by reacting TMC/PMDC/BTDC cyclic carbonate aqueous dispersion with diamines. The WNIPU coatings all displayed excellent chemical resistance to toluene, xylene, alcohol and 5% H2SO4 as well as high gloss, impact resistance, adhesion, flexibility and hardness. The Tg of WNIPUs was in the range of 31.4 °C–100.2 °C. All the WNIPUs coatings have good thermal stability with 5% weight loss temperatures (T5%) above 242 °C.