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This work is the first attempt to prepare microporous polytetrafluoroethylene (PTFE) fibrous layers embedded with aerogels/phase change materials. For preparation of this layer, the needle-less electrospray technology of water dispersion of individual components is used. Microstructure characteristics, including surface morphology and particle size distribution, and various properties of the prepared materials were investigated and explained. Transport performance of the fibrous layers embedded with aerogels/phase change materials, such as the transmission of heat, air, and water vapor was evaluated and discussed in details. It was found that the electro-sprayed materials composed by spherical particles with rough surface had compact disordered stacking structure. Aerogels and phase change materials (PCMs) play different roles in determining structural parameters and transport properties of the materials. Those parameters and properties could be flexibly adjusted by optimizing the spinning parameters, changing the content or proportion of the fillers to meet specific requirements. [ABSTRACT FROM AUTHOR]

The popularity of flexible energy harvesters has grown rapidly in recent decades because of their high flexibility for application in wearable and implantable devices. Flexibility and functionality are key issues for their use in wider engineering applications. In this study, we present a multifunctional flexible energy harvester based on aligned lead zirconate titanate (PZT)/shape memory polyurethane (SMPU) nanofibers and applying its shape memory properties for use with surfaces with curved and/or complex structures. Mechanical and thermomechanical analyses and energy harvesting tests were performed on random and aligned nanofibers to investigate the influence of nanofiber orientation and its shape memory properties. Our results showed that, compared with random nanofibers, 0° aligned PZT/SMPU nanofibers (the nanofibers' direction is parallel to the tensile direction) demonstrated higher mechanical, shape memory and energy harvesting properties. In particular, the energy harvesting properties (output voltages) were increased by 5.4 times. In addition, taking advantage of the shape memory effect, the PZT/SMPU energy harvester can be deformed into various curved shapes to match complex structures while maintaining its original piezoelectric characteristics, which resulted in enhanced energy harvesting from curved surfaces. The developed energy harvester realized better piezoelectricity as a result of its nanofiber arrangement, and offers a flexible ability to match various surfaces with complex structures to achieve more effective energy harvesting. [ABSTRACT FROM AUTHOR]

Abstract: The purpose of this study was to investigate the effect of amino acid on the morphology and crystallinity of nano-sized hydroxyapatite (HAP) crystals via a chemical precipitation method in the presence of l-lysine and l-tyrosine at different concentrations. The products were characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. The results showed the effect of l-lysine and l-tyrosine on the crystal growth of HAP was at opposite poles, i.e., the crystal growth was inhibited by l-lysine but promoted by l-tyrosine depending on the amino acid content. The mechanism of HAP crystal growth was also proposed. [Copyright &y& Elsevier]

Abstract: The purpose of this study was to investigate the effect of silk sericin (SS) on the morphology and crystallinity of hydroxyapatite (HAp) crystals synthesized at the pH 7.4–12 and 50°C via a biomimetic method. Using X-ray diffraction (XRD), transmission electron microscope (TEM) and high-resolution transmission electron microscope (HRTEM), it was revealed that a homogeneous assembly could be obtained in the presence of SS, which held a highly ordered microstructure and poor crystallinity. But in the absence of SS, an oriented aggregate could be prepared at 50°C and pH 10, which held more confused crystal lattice lines. The results proved that the biomimetic structure of HAp could be constructed under the controlled reaction conditions, which may offer a new clue on the understanding of the process of biomineralization. [ABSTRACT FROM AUTHOR]

• Biosynthesis of Au NPs was facially achieved using an alkali chitosan solution. • Dissolved chitosan with anchored Au NPs were self-assembled into a 3D architecture. • Well dispersed Au NPs with nanogaps led to excellent SERS EF and reproducibility. • Shapable, porous and pH-sensitive feature promoted good molecular selectivity. As a cost-efficient method for detecting analyses at trace level, chitosan-based surface-enhanced Raman scattering (SERS) sensor is a promising alternative. However, research on this technique is frequently hindered to complicated operations, dissatisfactory sensing and reproducible property. Herein, a biosynthesis of Au nanoparticles (NPs) was facially achieved through adding AuCl 4 ions into a dissolved alkali chitosan dope without using any heating operation or extra reductant. Subsequently, through hydrogen bonds-driven self-assembly during the coagulation process, chitosan nanofibrils anchored with Au NPs grew into a three-dimensional (3D) architecture. Because of the well-dispersed Au NPs with a content of 0.91–2.78 wt% and emerged sub-10 nm nanogaps, the prepared Au-embedded chitosan (Au@CS) nanocomposite could serve as excellent SERS substrate. The enhancement factor approached 107 and spot-to-spot reproducibility could be as low as 5.66% for detecting 4-mercaptobenzoic acid (4-MBA). Besides, owing to the innate pH-sensitive characteristic, the SERS substrate demonstrated molecular-selective detection of charge dye molecules. Furthermore, thanks to its hierarchical porosity and mechanical flexibility, straightforward trace detections of melamine in milk and pesticides on the fruit surface were realized using this SERS substrate. This simple and highly efficient SERS substrate provides great opportunity in the field of environmental management and food safety. [ABSTRACT FROM AUTHOR]

Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer known for its excellent hydrophobic properties. In this work, samples from PTFE dispersions with different combinations of water and carbon microparticles were prepared using an electrospraying method. The morphologies and sizes of carbon particles were investigated and the properties of layers including roughness, hydrophobicity and electrical resistivity were investigated. The non-conductive carbon microparticles were selected as a model particle to check the compatibility and electrospraying ability, and it had no effect on the hydrophobic and electrical properties. Carbon microparticles in polymer solution increased the degree of ionization and was found to be beneficial for the shape control of materials. The results showed that PTFE dispersion with the composition of water and carbon microparticles produced fine sphere particles and the layer fabricated with increased roughness. It was also found that the electrical resistivity and hydrophobicity of all the layers comparatively increased. The fabricated microporous layers can be used in various applications like interlining layer in multilayer textile sandwiches. [ABSTRACT FROM AUTHOR]

Robust, metal-free, macroscopic 3D porous CN/CE hybrid photocatalyst was fabricated by the co-assembly of g-C 3 N 4 and cellulose substrate, in which such an interconnected porous network facilitates mass transport, strong adsorption and multireflection of incident light. Consequently, the CN/CE hybrid photocatalyst exhibited both an excellent adsorption capacity and improved photocatalytic activity toward methylene blue degradation with degradation rate of 99.8%. • Robust, metal-free, 3D porous g-C 3 N 4 /cellulose hybrid photocatalyst was fabricated. • Highly porous network facilitates mass transport, adsorption and light multireflection. • Syncretic interface between g-C 3 N 4 and cellulose increases photoelectrons transfer. • Methylene blue removal ratio over the CN/CE hybrid photocatalyst reaches up to 99.8%. • The CN/CE hybrid photocatalyst exhibits mechanical stability and high reusability. Robust, metal-free, macroscopic 3D porous g-C 3 N 4 /cellulose (CN/CE) hybrid photocatalyst was successfully fabricated by the co-assembly of g-C 3 N 4 and cellulose substrate. The morphology, structure, mechanical property, optical and electrochemical performances, and photocatalytic activity of the CN/CE were investigated in detail. The obtained CN/CE hybrid photocatalyst possessed homogeneous 3D interconnected network structure, excellent mechanical strength and considerable recyclability. Also, the CN/CE hybrid photocatalyst exhibited both an excellent adsorption capacity and improved photocatalytic activity toward methylene blue (MB) degradation with degradation rate of 99.8%, much higher than that of pure g-C 3 N 4 (54.2%). The enhanced photocatalytic performance of CN/CE derived from the synergistic effects of homogeneous 3D interconnected network structure and syncretic interfaces between g-C 3 N 4 and cellulose, facilitating mass transport, light absorption and reactant adsorption, as well as the transfer of the photogenerated electrons. Moreover, the CN/CE hybrid photocatalyst indicated a high reusability and stability without significant reduction in its efficiency with nearly 96% of MB degradation after four cycles. This work not only demonstrated the importance of homogeneous interconnected network structure to prepare highly effective photocatalyst, but also provided a new insight into the approach for design and utilization of stable and recyclable metal-free photocatalyst for visible light derived contaminant degradation. [ABSTRACT FROM AUTHOR]

• Smart nonwoven fabric with reversible double-stimulus response wettability was fabricated. • DSR-CZPP can adjust wettability and permeability under various stimulations of pH and UV light. • DSR-CZPP with CNC/ZnO simultaneously degrade organic dyes and tailor oil-water separation. • DSR-CZPP had high removal rates for various pollutants (metal ions, toxic organic solvents). This work presents the first fabrication of smart nonwoven fabric (DSR-CZPP) with extraordinary reversible double-stimulus responsive wettability, where carboxyl groups of cellulose nanocrystals/zinc oxide (CNC/ZnO) nanohybrids deposited on fabric surface can bond with hydroxyl group of the PDMAEMA-b-PHEMA-b-PMAAAB triblock polymer brushes that was prepared by using methyl methacrylate (HEMA), dimethylaminoethyl methacrylate (DMAEMA) and methacrylamide-azobenzene monomer (MAAAB) via reversible addition–fragmentation chain transfer (RAFT). The peculiar reversible double-stimulus responsive wettability of the DSR-CZPP can be modulated by triggering hydrophilic/hydrophobic transitions and lipophilic/oleophobic transitions under dual-stimulations of pH and UV light irradiation. The special molecular structure of the triblock polymer brushes enabled DSR-CZPP to intelligent modulation of oil-water separation under the control of "UV & pH double switch", meanwhile CNC/ZnO simultaneously can induce the photocatalytic degradation of organic dyes. Moreover, DSR-CZPP can have high removal ratios of various pollutants, such as metal ion (Cu2+) and toxic organic solvent (silicone oil, acetone and chloroform). This smart and multifunctional fabric shows great potentials for treating complicated polluted water from most industrial fields. [ABSTRACT FROM AUTHOR]

• Phase change nanofibers (PCF) demonstrated solid–solid phase change performance. • Obtaining PCF composite with excellent shape-stability and energy storage efficiency. • PCF composite shows "on–off" drug release in response to phase change temperature. • PCF composite with 5 wt% f- CNC-ZnO displayed a sustained release of more than 78.9% within 336 h. Thermo/light-responsive functionalized cellulose nanocrystal-zinc oxide (f- CNC-ZnO) nanohybrids based poly (3-hydroxybutyrate-co-3-hydroxy valerate) (PHBV) phase change nanofiber (PCF) composites with highly thermal energy storage ability were developed for controllable drug release applications. Under sunlight irradiation, the PCF composite (without f- CNC-ZnO) absorbed light and stored the thermal energy with 46.3% efficiency. An "on–off" temperature regulation of tetracycline hydrochloride (TH) release was found for PCF composites according to phase change temperature. At the temperature close to the melting point of PEG at 60 °C, the PCF composite with 5 wt% f- CNC-ZnO displayed a sustained release of more than 40.5 and 78.9% of tetracycline hydrochloride (TH) were released over two weeks for the 10 and 30 wt% drug loading. Thus, the PCF composites with excellent thermo/light-responsive properties and high energy storage efficiency are beneficial for promising sustainable thermal storage and drug delivery systems. [ABSTRACT FROM AUTHOR]

The recently-developed MOFs-based hydrogels and aerogels can overcome the disadvantages of powdered MOFs such as fragile, unstable, unprocessable and unrecoverable, which has become a hot topic now. Here, we summarize the recent progress in the preparation of MOFs-based hydrogels and aerogels as well as their applications in drug control release, wound healing, sensing, energy storage, catalysis, water treatment, and gas adsorption applications. • This paper reviewed the recent progress in metal-organic frameworks-based hydrogels and aerogels. • The categories of metal-organic frameworks-based hydrogels and aerogels were divided in detail. • Key application fields of metal-organic frameworks-based hydrogels and aerogels were discussed. • Future outlook for metal-organic frameworks-based hydrogels and aerogels. In recent years, metal-organic frameworks (MOFs) have attracted incredible chemical and material research interests because of their prominent properties and charming structures. The reliable production of a wide variety of MOFs materials and MOF derivatives, such as MOF-metal nanoparticles composites and MOFs-polymers hybrids, offers many possibilities to develop MOF-based applied materials. Although MOFs have many unique features, including abundant pore structures and multiple functional ligands, their applied performance is limited by intrinsic fragility and powdered crystalline state, as well as unsatisfied stability and processability. By this, MOF-based hydrogels and aerogels have achieved unparalleled results, outperforming ungelated MOFs materials in many aspects. This review presents current developments of MOF-based hydrogels and aerogels with emphasis on the specific categories and the synergistic effects of MOF-derived aerogels between MOFs and additional materials. Particular emphasis is placed on discussing the advantages of MOF-based hydrogels and aerogels in applications such as sensors, batteries, supercapacitors, adsorbents, catalysts etc. MOF-based hydrogels and aerogels can provide valuable guidance for the investigation of MOFs towards practical applications with processability, stability, and easy handling. Specifically, we will summary recent progress of pure MOF hydrogels, MOF@biology derived organic macromolecules hydrogels, MOF@biocompatible hydrogels, MOF@ graphene hydrogels, pure MOF aerogels, MOF@silica aerogel composites, MOF@ graphene aerogel composites, MOF@cellulose aerogel composites, and aerogel composites containing MOFs-derived materials. In addition, their applications are also discussed. We hope that this review will be helpful for those who want quick access to valuable references about MOF-based hydrogels and aerogels and their applications. [ABSTRACT FROM AUTHOR]