Biomimetics
·
2023
·Vol. 8
·期 2
·196
·
IF 4.5
Shuyi Li,Zhengyi Song,Yuyan Fan,Dongsong Wei,Yan Liu
Liquid crystal elastomers (LCEs) are polymer networks that exhibit anisotropic liquid crystalline properties while maintaining the properties of elastomers, presenting reversible high-speed and large-scale actuation in response to external stimuli. Herein, we formulated a non-toxic, low-temperature liquid crystal (LC) ink for temperature-controlled direct ink writing 3D printing. The rheological properties of the LC ink were verified under different temperatures given the phase transition temperature of 63 °C measured by the DSC test. Afterwards, the effects of printing speed, printing temperature, and actuation temperature on the actuation strain of printed LCEs structures were investigated within adjustable ranges. In addition, it was demonstrated that the printing direction can modulate the LCEs to exhibit different actuation behaviors. Finally, by sequentially conforming structures and programming the printing parameters, it showed the deformation behavior of a variety of complex structures. By integrating with 4D printing and digital device architectures, this unique reversible deformation property will help LCEs presented here apply to mechanical actuators, smart surfaces, micro-robots, etc.Keywords:liquid crystal elastomers;temperature-responsive;programmable shape-changing;4D printing
研究领域:
材料科学
·
机械工程
·
纳米技术
·
机器人技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF POLYMER RESEARCH
·
2012
·Vol. 19
·期 11
·1-7
·
IF 1.733
Yu Wei-Na,Liu Shou-Xin,Wang Hong-Mei,Tian Rong
Temperature-responsive P(NIPAM- co -HMAM)- b -PEO- b -P(NIPAM- co -HMAM) triblock copolymers were synthesized by an atomic transfer radical polymerization (ATRP) method without freeze–pump–thaw cycles. The composition, structure, and molecular weight of the synthesized block copolymer were characterized by 1 H NMR and GPC. The phase transitions induced by temperature for different copolymers in dilute aqueous solutions have been studied using transmittance measurements, laser particle size measurements, viscosity analysis, and surface tension measurement, which showed that the HMAM content and the PEO (or PEG) chain length in the synthesized triblock copolymer affects the copolymer’s lower critical solution temperature (LCST). The micellization behavior of each temperature-responsive triblock copolymer was investigated by fluorescence probe measurements and transmission electron microscopy (TEM), which showed that the triblock copolymers form stable micelles above the LCST. The introduction of the HMAM component and the formation of micelles represent the first steps in the development of an injectable gel that forms in situ through chemical and physical crosslinking.
研究领域:
高分子化学
·
生物材料
·
药物递送系统
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2021
·Vol. 138
·期 44
·51315
·
IF 3.125
Bowen Xu,Feilong Han,Xuqiang Pei,Xin Liu,Junying Zhang,Jue Cheng,Jingbo Zhao
Increasing the molecular weight of polyurethanes (PU) is an effective way to improve its mechanical properties, while, it is at the expense of sacrificing processability. Congruent modification in both mechanical and processing performances is still a challenge. Here, bis-phenol-A (BPA) derivatives, including tetrachlorobisphenol-A and tetrabromobisphenol-A, were chosen as the extender to synthesize thermoplastic PUs (TPU) containing blocked isocyanate units. This blocked isocyanate has a temperature-responsive reversible reaction due to phenol urethane bonds, so as to ensure the good mechanical properties at the service temperature and better processing performance via deblocking into smaller molecular weight at the processing temperature; in addition, negative induction effect of the halogen substituents endow BPA derivatives with deblocking reaction at lower temperature. The experimental results confirmed that the blocking reaction carried out completely at 70°C, and accompanying by the dramatical increase of molecular weight. The obvious deblocking reaction happened at 140°C, where the average molecular weight of TPUs decreased from 22,600 g/mol to 13,690 g/mol. Meanwhile, the melt flow index increased significantly with the extension of heating time, indicating that the PU has good processing properties. After the deblocking and re-blocking reactions were repeated alternatively, there is almost no change in its tensile properties, molecular weight and melt outflow index within two cycles under air atmosphere. This article proposes a strategy of congruent modification in both mechanical and processing performances of TPU.
研究领域:
材料科学
·
聚合物化学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2020
·Vol. 8
·期 35
·12092-12099
·
IF 7.059
Jian Liu,Weizhong Xu,Zhongwen Kuang,Pengli Dong,Youxing Yao,Huaping Wu,Aiping Liu,Fangmin Ye
Smart hydrogels play a vital role in fundamental research and industrial applications in the fields of biosensors, flexible devices and intelligent human–machine technologies; however, developing a simple, low-cost and large-scale method to obtain hydrogel actuators with rapid response and robust and steadily controllable motion remains a big challenge. In this work, a temperature-responsive, gradient structured hydrogel with quick bending and adjustable actuation was fabricated by the copolymerization of the N-isopropylacrylamide (NIPAM) monomer with dispersed montmorillonite (MMT) via a facile precipitation method. The introduction of MMT with good thermal conductivity made the volume phase transition of the PNIPAM-based hydrogel occur earlier, and the deformation degree and bending direction could be adjusted by changing the MMT content. The representative composite hydrogel with 0.2 g MMT in the precursor presented bidirectional bending characteristics with a bending amplitude of about 289° and an average bending speed of about 36.0° s−1, while the composite hydrogel with 0.3 g MMT in the precursor only possessed a unidirectional bending ability with a bending amplitude of about −259° and a bending velocity of about −28.8° s−1 due to the great difference in the shrinking capacity between the top and bottom sides of the composite hydrogel. In addition, flexibly controllable deformation was specially realized by a well-designed patterned hydrogel with a local component and a thickness difference. Our work provides a practical method for the ingenious design of a hydrogel for further development of programmable and versatile hydrogel-based smart actuators and soft robots.
研究领域:
材料科学
·
生物医学工程
·
软体机器人
·
智能材料
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2019
·
IF 3.131
Hui Zhao,Ying Li
Tremella polysaccharide , a novel polysaccharide , not only has good ability of film forming, but also has excellent physiological functions, which was suitable to be used to prepare eco-friendly hydrogels. In this study, a novel pH/temperature responsive micelle-laden hydrogel based on tremella polysaccharide (WSK), carboxymethyl cellulose (CMC) and nonionic surfactant-decyl polyglucoside (C 10 APG) was fabricated through radical polymerization by crosslinking N-isopropylacrylamide (NIPAM), for the purpose to achieve controlled release of hydrophobic drugs indomethacin (IND). Firstly, WSK/CMC/PNIPAM hydrogels were prepared and their characteristics were investigated by FTIR, TGA , SEM, rheological and compressive tests as well as swelling experiments. Then the hydrophobic drug IND molecules were solubilized in C 10 APG micelles which were uniformly dispersed in the WSK/CMC/PNIPAM/C 10 APG networks. Lastly, the IND release behavior of WSK/CMC/PNIPAM/C 10 APG hydrogels was studied, which exhibited both pH and temperature sensitivity. The obtained WSK/C 10 APG-based pH/temperature sensitive hydrogel may have potential in biomedical applications such as drug vehicles and tissue engineering.
研究领域:
材料科学
·
药学
·
生物医学工程
·
高分子化学
✓ 已验证
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2020
·Vol. 31
·期 3
·2006839
·
IF 16.836
Bingbing Gao,Maoze Guo,Kai Lyu,Tianshu Chu,Bingfang He
Wounds, especially those caused by chronic diseases, are severe threats to human health. To facilitate their recovery, considerable efforts have been devoted to the generation of wound tissues and the detection of wound biomarkers. Here, an intelligent origami silk fibroin microneedle-structured dressing (i-SMD) with a smart drug release system, biochemical sensing, and physiological monitoring ability for epidermal sensing and wound healing, is presented. By utilizing temperature-responsive N -isopropylacrylamide (NIPAM) hydrogel and inverse opal (IO) photonic crystals (PCs) as a smart drug release system, controllable drug release is achieved on the i-SMD. The patterned microfluidic channels on the i-SMD and IO PCs enable the liquid to flow spontaneously in the channels, thereby achieving sensitive multiple biochemical analysis of inflammatory factors; meanwhile, microelectronic circuits integrated on the i-SMD enable sensitive motion monitoring. Notably, the performance of i-SMD in facilitating wound healing is demonstrated by treating full-thickness cutaneous wounds in a diabetic mouse model, indicating the remarkable prospects of i-SMD in wound management and other related biomedical fields.
研究领域:
生物医学工程
·
材料科学
·
伤口护理
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药物递送系统
·
传感技术
✓ 已验证
产品关联
DOI
高影响因子
Biomass Conversion and Biorefinery
·
2022
·
IF 4.05
Shang Xian-chao,Zhang Yu-qin,Zheng Yan-fen,Li Yiqiang
Polyphenols and flavonoids are abundant in spent onion skins (SOSs), being present in amounts are 2–sixfold greater times of than those in the inner bulb. In this study, an eco-friendly and efficient extraction method based on temperature-responsive deep eutectic solvents (TRDESs) was used to obtain natural flavonoids from SOSs. Microwave-assisted extraction yields of quercetin, kaempferol, luteolin, and quercetin-3-O-β-D-glucoside were evaluated to determine the efficiencies of a series of TRDESs. An extraction system composed of ethanolamine and m -cresol at ratio of 1:1 (20% water in TRDES system) was found to possess the highest efficiency. The extraction conditions were screened and optimized for efficiency using a Box-Behnken design. As a result, an extraction power of 554 W, extraction temperature of 76 °C, extraction time of 16 min, and solid–liquid ratio of 14 mg/mL were determined to be the optimal conditions. Under these extraction conditions, the total flavonoid extraction yields reached 47.83 ± 0.21 mg/g. The macroporous resin HPD 600 was selected for the separation and recovery of the TRDESs extraction mixture and the experimental measurements revealed that it allowed recovery rate more than 90%. In vitro activity testing of the flavonoid extract demonstrated excellent FRAP assay, DPPH assay and ABTS assay results for the SOSs extract prepared using a TRDES, and its inhibitory effects on S. aureus , E. carotovora , and B. subtilis were marked.
研究领域:
化学工程
·
环境科学
·
药学
·
食品科学
·
分析化学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2024
·
IF 5.6
Xinlin Zhang,Xinyu Yan,Zihui Cai,Lina Fu,Xinyue Dong,Jihong Cui,Hangrong Zheng,Mingyue Xu,Yujie Fu
In the current work, a temperature-responsive system consisting of a fatty acid-based hydrophobic deep eutectic solvent and a choline chloride (ChCl)-based hydrophilic deep eutectic solvent was innovatively developed. It was used to extract and separate polar compounds (chlorogenic acid, rutin, hyperin, isoquercetin, hydroxy-α-sanshool) from Zanthoxylum bungeanum Maxim. peels (ZBMP). Different molar ratios of the hydrophobic deep eutectic solvent (DES) composed of decanoic acid (DA)-octanoic acid (OA) and hydrophilic DES composed of ChCl-levulinic acid (Lev) were chosen as the switching medium. Under the optimal extraction conditions, the TRBDES consisting of hydrophilic DES (ChCl: Lev/1:2): hydrophobic DES (OA: DA/2:1): H 2 O (v/v/v,5/5/1) demonstrated a greater total extraction rate and distributive efficiency than the conventional solvents. High DPPH radical scavenging capacity of target compounds (IC 50 = 0.29 mg/mL) from the bottom phase recovered by D101 macroporous resin. Hydrogels prepared by DES containing extracts in the top phase showed significant inhibition of E. coli (15.5 ± 0.7 mm). and S. aureus (21.0 ±1.4 mm). The solvent morphologies and the intrinsic switching mechanism were observed and illustrated. Moreover, density functional theory (DFT) calculations showed that hydrogen bond production is crucial for extraction. This work provides a resource for exploring and utilizing TRBDES for environmentally friendly extraction of various bioactive active ingredients from plant sources.
研究领域:
化学
·
药学
·
食品科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Jiahao Dong,Jiexiang Tong,Jing Luo,Xiaoya Liu
In this work, a novel kind of temperature-responsive core cross-linked star (CCS) polymer, composing of poly(methoxypolyethylene glycol-co-di(ethylene glycol) ethyl ether acrylate) (P(PEGA-DEGA)) as thermo-responsive arm and poly(2-(dimethylamino)ethyl methacrylate) as functional core, was developed as nanoreactor for immobilizing gold nanoparticles for smart catalyst with facile recovery. The protonated imino groups in CCS polymer core could capture AuCl 4 - and simultaneously reduce it to Au NPs in aqueous solution, leading to the formation of P(PEGA-DEGA) CCS@Au composite. The whole procedure was carried out in aqueous media without using any toxic reducing agent, which is facile, efficient and green. The as-prepared CCS@Au composite exhibit a superior high catalytic activity for the reduction of 4-nitrophenol (4-NP), owing to that the soluble polymeric arms of the CCS polymers provides a homogeneous reaction system with fast mass transfer and thus facilitates interactions between Au NPs in the core and 4-NP. In addition, temperature-responsive catalyzing behavior was observed for the CCS@Au composite: the reaction rate enhanced with the elevation of the reaction temperature at first, but decreased when the temperature increased close to the LCSTs of the CCS@Au catalysts.
研究领域:
材料科学
·
纳米技术
·
催化
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）