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Solar‐driven interfacial evaporation (SDIE) has attracted great attention by offering a zero‐carbon‐emission solution for clean water production. The manipulation of the surface structure of the evaporator markedly promotes the enhancement of light capture and the improvement of evaporation performance. Herein, inspired by seedless lotus pod, a flexible pristine polypyrrole (PPy) membrane with macro/micro‐bubble and nanotube asymmetric structure is fabricated through template‐assisted interfacial polymerization. The macro‐ and micro‐hierarchical structure of the open bubbles enable multiple reflections inner and among the bubble cavities for enhanced light trapping and omnidirectional photothermal conversion. In addition, the multilevel structure (macro/micro/nano) of the asymmetric PPy (PPy‐A) membrane induces water evaporation in the form of clusters, leading to a reduction of water evaporation enthalpy. The PPy‐A membranes achieve a full‐spectrum light absorption of 96.3% and high evaporation rate of 2.03 kg m−2 h−1 under 1 sun. Long‐term stable desalination is also verified with PPy‐A membranes by applying one‐way water channel. This study demonstrates the feasibility of pristine PPy membranes in SDIE applications, providing guidelines for modulation of the evaporator topologies toward high‐efficient solar evaporation. A seedless lotus‐pod‐inspired asymmetric pristine PPy (PPy‐A) membrane is fabricated via template‐assisted interfacial polymerization for solar‐driven interfacial evaporation. The hierarchical macro/micro open bubbles enhance light absorption of PPy‐A membrane, facilitating omnidirectional photothermal conversion. The unique multilevel structure of PPy‐A membrane induces water evaporation in cluster form, leading to low evaporation enthalpy, achieving highly efficient solar evaporation.

Silk fibroin has been widely used in biomedical and clinical fields owing to its good biocompatibility. In the present work, self-crosslinking of fibroin molecules was carried out using the hydrogen peroxide (H 2 O 2 )-horseradish peroxidase system, followed by preparation of the fibroin membranes, aiming at improving the mechanical property of fibroin-based material and expanding its applications. P-Hydroxyphenylacetamide (PHAD), as the model compound of tyrosine residues in fibroins, was used to investigate the possibility of horseradish peroxidase (HRP)-catalyzed crosslinking. The results were characterized by means of 1H NMR and UPLC-TQD. The efficacy of enzymatic crosslinking of silk fibroins was examined by determining the changes in the relative viscosity, amino acid compositions, and SEC chromatogram. The obtained data indicated that H 2 O 2 -HRP incubation led to PHAD polymerization, and the molecular weight of fibroin proteins was also noticeably increased after the enzymatic treatment. CD and ATR-FTIR spectra revealed that H 2 O 2 -HRP treatments had an evident impact on the conformational structure of silk fibroins. The mechanical property and thermal behavior for the modified fibroin membrane were noticeably improved compared to the untreated. Meanwhile, the obtained membrane exhibited good biocompatibility according to the cell growth experiment. The present work provides a novel method for preparation of the fibroin-based materials for biomedical applications.

Conventional silane treatment can increase the hydrophobicity of natural cellulosic fibers. This report employs a combination of alkali and dipodal silane treatments. Bridged bis (3-trimethoxysilylpropyl) amine (BAS), a dipodal silane, was used instead of regular ones to enhance the hydrophobicity of ramie plain-woven fabrics. Before silane application, alkali treatment conditions’ impact on mechanical properties was optimized using response surface methodology (RSM). The desirability function approach and graphical optimization techniques were employed to find out the optimum condition. The RSM demonstrated that a concentration of 6.11% alkali, a duration of 30 min, and a temperature of 39.10 °C yielded the optimal conditions, resulting in a breaking force of 518.27 N and an elongation of 23.36%. After optimization of parameter, alkali treatment of the fabric was carried out. These alkali-treated fabrics were then bulk-treated with BAS. The Taguchi L9 orthogonal array experimental design was applied to identify a variable that has the highest impact on the hydrophobicity. Furthermore, BAS’s impact on water contact angle (WCA), surface morphology, and thermal properties was investigated. Alkali-treated ramie fabrics absorb water due to hemicellulose and lignin removal. However, BAS treatment resulted in a hydrophobic ramie fabric surface, as the combined alkali and BAS-treated fabrics exhibit a WCA greater than 94°, reaching 113.85°. According to thermo-gravimetric analysis, combined alkali and silane treatment improved the degradation temperature of fabrics to 403.25 °C. This improvement is attributed to the formation of six, rather than three, Si–O bonds on the ramie fabric surface.

This paper investigates the production of hydrothermal responsive shape memory filaments with different draw ratios (0.8, 2.0 and 3.2) using microcrystalline cellulose (MCC) as a filler and shape memory polyurethane (SMPU) as a matrix. A mechanical-thermo-aqueous programming test was conducted to study the shape-memory properties of the microcomposite filaments. The effect of draw ratio and triggering temperature on mechanical, physical, thermal, morphological, and shape memory properties was thoroughly studied. Among the microcomposite filaments, SMPU-MCC with a draw ratio of 2.0 exhibited the highest tenacity value of 0.91 cN/dtex in its original shape with an elongation of 385.2%. The differential scanning calorimetry results showed that the glass transition temperature (Tg) of the filaments increased as the draw ratio increased from 0.8 to 3.2, ranging from 38.35 to 41.02 °C. The crystallinity percentages obtained for pure SMPU, SMPU-MCC-0.8, SMPU-MCC-2.0, and SMPU-MCC-3.2 were 27.10%, 30.68%, 38.72%, and 36.88%, respectively. In addition, an optimum draw ratio led to a degradation temperature rise from 372.5 to 391.3 °C which shows the thermal stability of the filaments was significantly influenced by the intermolecular bonding between MCC and SMPU, which intensified as the draw ratio increased from 0.8 to 2.0. Moreover, the filaments exhibited excellent mechanical and thermal properties in six cycles at the optimum draw ratio and triggering temperature indicating their future application for repeated use without experiencing major changes in shape memory properties.

Silk fibroin (SF) can be extensively utilized in biomedical areas owing to its appreciable bioactivity. In this study, biocompatible composites of SF and hydroxyapatite (HAp) were fabricated through in situ biomimetic mineralization process. Graft copolymerization of acrylic acid (AA) onto SF was conducted by using the catalytic system of acetylacetone (ACAC), hydrogen peroxide (H2O2) and horseradish peroxidase (HRP), for enhancing the deposition of apatite onto the fibroin chains. Subsequently, biomimetic mineralization of the prepared fibroin-based membrane was performed in Ca/P solutions to synthesize the organized SF/HAp composites. The efficacies of graft copolymerization and biomimetic mineralization were evaluated by means of ATR-FTIR, GPC, EDS-Mapping, XRD and others. The results denoted that AA was successfully graft-copolymerized with fibroin and formed the copolymer of silk fibroin-graft-polyacrylic acid (SF-g-PAA), and the grafting percentage (GP) and grafting efficiency (GE) under the optimal condition reached to 23.2% and 29.4%, respectively. More mineral phases were detected on the surface of SF-g-PAA membrane after mineralization process when compared to that of the untreated fibroin membrane, companying with an improved mechanical property. According to MG-63 cell viability and fluorescent adhesion assays, the mineralized SF-g-PAA composite showed satisfactory biocompatibility and exceptional adhesive effects as well. The synthetized composite of SF-g-PAA/HAp can be potentially applied in the fields of bone tissue engineering.

Silk fibroin has been widely used in biomedical and clinical fields owing to its good biocompatibility. In the present work, self-crosslinking of fibroin molecules was carried out using the hydrogen peroxide (H O )-horseradish peroxidase system, followed by preparation of the fibroin membranes, aiming at improving the mechanical property of fibroin-based material and expanding its applications. P-Hydroxyphenylacetamide (PHAD), as the model compound of tyrosine residues in fibroins, was used to investigate the possibility of horseradish peroxidase (HRP)-catalyzed crosslinking. The results were characterized by means of 1H NMR and UPLC-TQD. The efficacy of enzymatic crosslinking of silk fibroins was examined by determining the changes in the relative viscosity, amino acid compositions, and SEC chromatogram. The obtained data indicated that H O -HRP incubation led to PHAD polymerization, and the molecular weight of fibroin proteins was also noticeably increased after the enzymatic treatment. CD and ATR-FTIR spectra revealed that H O -HRP treatments had an evident impact on the conformational structure of silk fibroins. The mechanical property and thermal behavior for the modified fibroin membrane were noticeably improved compared to the untreated. Meanwhile, the obtained membrane exhibited good biocompatibility according to the cell growth experiment. The present work provides a novel method for preparation of the fibroin-based materials for biomedical applications.