查找使用阿拉丁产品的科研文献

Self-Healing, Water-Retaining, Antifreeze, Conductive PVA/PAA-PAM-IS/GC Composite Hydrogels for Strain and Temperature Sensors

Jinbiao Min,Zhaoxi Zhou,Jia Zheng,Caibin Yan,Hongyuan Sha,Maochun Hong,Heqing Fu

In this paper, PVA/PAA-PAM-IS/GC composite hydrogels are prepared using polyvinyl alcohol (PVA), poly acrylic acid (PAA), poly acrylamide (PAM), and iron sulfate hydrate (IS) glycerol (GC). The crosslinking network is formed by the coordination of carboxyl groups with ions, which forms PVA with semi-interpenetrating network. The mechanical properties and self-healing properties of PVA/PAA-PAM-IS/GC composite hydrogels are excellent. The stress, strain and self-healing efficiency of PVA/PAA-PAM-IS/GC composite hydrogels can reach 840 kPa, 784%, and above 95%, respectively. The antifreeze and water retention properties of PVA/PAA-PAM-IS/GC composite hydrogels are improved by glycerol. PVA/PAA-PAM-IS/GC composite hydrogels remains flexible at low temperatures and moist for a long time at room temperature. The conductivity of the hydrogel increases with the increase of temperature because the interactions between glycerol, water molecules and ammonium ions are affected by the temperature, the multifunctional conductive hydrogel can be used in strain sensing and temperature sensing. In summary, PVA/PAA-PAM-IS/GC composite hydrogels can provide a guide in the field of electronic intelligence.

Preparation of a PVA/CNF/ETOS Elastic Aerogel by Directional Freezing and Its Application in Oil–Water Separation

Boyuan Chen,Hui Zhang,Lijuan Li,Yingcheng Hu

Nano-cellulose aerogels have low densities, high porosities, and strong absorption capacities, making them suitable for cleaning up oil and chemical spills in oceans. However, their weak lipophilicity and poor mechanical properties often limit their applications. We attempted to introduce long-chain polymers on the nanocellulose/polyvinyl alcohol (CNF/PVA) surface for the hydrophobic modification of aerogels. In this paper, PVA/CNF was silylated by introducing hydrolyzed ethyltrimethoxysilane to increase its hydrophobicity. Aerogels with interpenetrating pore structures were prepared by a directional freezing method. The aerogels had a high strength in the freezing direction and high compressive elasticity in the direction perpendicular to the freezing direction. Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, and water contact angle (148°) tests demonstrated the successful silylation of the aerogel surface. The aerogel absorbed oil and some organic solvents 50–110 times higher than its own weight. It showed good reusability, with an absorption loss rate of 20% after 40 squeezing cycles. This green and sustainable method is inexpensive and has a short production cycle. In addition, the absorption of alcohols and lipids by aerogels can be used as a carrier for surgical drugs.

Effects of glycerol and PVA on gelatin/Gum Arabic aerogels: Microstructure, mechanical properties, and applications for food monitoring

Binghang Li,Miaomiao Chen,Yuan Wu,Bing Liu,Gangliang Huang

Smart labels are a hot research topic in the field of food science , but the low sensitivity of film smart labels limits the on-site and visual detection of seafood freshness. To address these challenges, betacyanin (BET) as a response signal and an aerogel smart label based on gelatin/gum arabic (Gel/GA) were designed. The labels produced a visually observable color change in the presence of volatile ammonia (2500 ppm) and displayed an immediate colorimetric response to food spoilage when packaged shrimp was used as an example. The results showed that the smart aerogel labels were better than the film smart labels in the response sensitivity test of volatile ammonia. In addition, the addition of a small amount of plasticizers (glycerol) or hardeners (polyvinyl alcohol, PVA) further enhanced the responsiveness of the aerogel to volatile ammonia. Notably, the addition of a small amount of PVA further increased the hardness of the aerogels. The scanning electron microscopy (SEM), infrared spectroscopy, and X-ray diffraction (XRD) results showed that these results may be caused by the interpenetration of the PVA network and the Gel/GA network to form a new type of interpenetrating polymer network structure. Therefore, the developed smart aerogel labels play an important role in ensuring food quality and reducing food waste and inspire new ideas for the development of additional functional smart labels.

Self-assembled electrospun PVA/CMC/PEO composite fiber film material with enhanced dye adsorption performance for wastewater treatment

Chengfu Zhang,Ran Wang,Lexin Zhang,Zhiwei Liu,Dongxue Ning,Qing Li,Lili Gao,Tifeng Jiao

As society rapidly progresses, environmental issues, including water pollution and ecosystem degradation are steadily worsening. In this work, a novel functional nanofiber composite film based on polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), and polyethylene oxide (PEO) were prepared by using electrospinning technique. The incorporation of PEO facilitated a more concentrated nanofiber diameter distribution. The prepared composite films were further modified with glutaraldehyde vapor to enhance their hydrophobicity and improve pore-making capabilities on the fiber surface. The nanocomposite fiber film, with its simple preparation process, cost-effectiveness, and environmental friendliness , exhibits a promising prospect in addressing environmental challenges. Notably, the designed nanofiber films demonstrated remarkable efficiency in dye adsorption, owing to the high specific surface area of the fibers and the selective binding of active groups on the fiber surface to the dyes. Moreover, they showed good reusability, which is of great significance for adsorbents. Therefore, the obtained composite films from environmentally friendly preparation process has great application potential in wastewater treatment and dye removal .

Camel skin-fat structure inspired MXene@PVA/PCC aerogel composite for efficient medium and low temperature infrared stealth

Qinghong Ji,Xinxin Sheng,Xiaolong Li,Shuang Liu,Qiufei Chen,Pengzong Guo,Yabi Yang,Youyou Huang,Guoliang Zhang,Xiang Lu,Jinping Qu

Infrared stealth materials are in increasing demand with the development of infrared detection technology. However, most reported materials focus solely on emissivity control or temperature control, resulting in brief and less ideal infrared stealth effect. Herein, a double layer MXene@polyvinyl alcohol (PVA)/phase change capsules (PCC) aerogel composite inspired by the skin-fat structure of camel for infrared camouflage was successfully fabricated via a facile freeze-drying followed by spraying method. The PVA/PCC aerogel composite with high latent heat (155.2 J/g) and strong mechanical properties (772.6 kPa), obtained by an in-situ one-step method, is adopted as a temperature control layer, benefiting from the prominent thermal insulation of porous structure and effective heat absorption of PCC. The low emissivity (0.249) of the MXene layer on the surface of aerogel composite makes its radiation temperature recognized by the thermal imager much lower than its actual temperature. By integrating thermal insulation, heat absorption and emissivity reduction strategies, MXene@PVA/PCC aerogel shows no difference with the background in the infrared thermal imager (radiation temperature difference less than 10 °C), achieving superior infrared stealth for medium and low temperature scenarios, and provides novel ideas for developing more high-performance infrared stealth materials.

High sensitive, stretchable and weavable fiber-based PVA/WPU/MXene materials prepared by wet spinning for strain sensors

Cheng Hengyi,Zuo Tongcheng,Chen Yixiang,Yu Dan,Wang Wei

With the advent of an ageing society, wearable strain sensors have great prospects for applications in artificial intelligence, motion detection and healthcare, and have attracted much attention from researchers. But the challenges of poor wear comfort, low sensitivity and clumsy appearance still greatly limited their practical applications. To address these problems, a facile strategy for the fabrication of fibrous strain sensors by wet spinning is proposed. Polyvinyl alcohol/waterborne polyurethane/MXene (PVA/WPU/MXene) is the main component to construct the conductive part of the fiber-based materials and aqueous calcium chloride solution is used as a coagulation bath in the spinning process. The relevant physicochemical properties of the resulting conductive fibers were characterized and tested. Though the facile wet-spinning process, an effective conductive network was achieved in the prepared stretchable sensor with excellent mechanical properties and chemical stability and can be woven into various fabric forms according to practical demanding. It was demonstrated that a sensitivity of 5.61 could be obtained with an elongation at break of over 358%. In addition, the sensing and weaving properties of the composite fibers were characterized, and application performance was measured by placing them on the elbow, wrist, and knee. As a result, the PVA/WPU/MXene composite fiber strain sensor displays a linear response, good sensitivity and cyclic stability and has great potential for wearable strain sensors and flexible strain sensors in complex environments

Immobilization of nitrifying bacteria in magnetic PVA–SA-diatomite carrier for efficient removal of NH4+-N from effluents

Yansong Zhang,Zehai Yu,Yunshuang Hu,Caifeng Song,Fuwei Li,Wen He,Xiaofeng Wang,Zhixia Li,Hongfei Lin

Magnetic polyvinyl alcohol–sodium alginate–diatomite (PVA–SA-diatomite) composite carriers for immobilized microorganisms were prepared for removal of NH 4 + -N from effluents. The mass transfer efficiency, chemical stability, and NH 4 + -N removal efficiency of the carriers were investigated. The amount of each ingredient added significantly affected the performance of the carriers. The optimal concentrations of PVA, SA, diatomite , and Fe 3 O 4 were 10%, 1%, 1%, and 2%, respectively. The obtained carrier achieved a NH 4 + -N removal efficiency of 72.5% after reaction for 12 h, which was 31.8% higher than that with the non-magnetic carrier. The removal of NH 4 + -N was attributed to the cooperative action among non-magnetic ingredients, magnetic ingredients, and microorganisms. The adsorptions of NH 4 + -N by non-magnetic ingredients and Fe 3 O 4 contributed 21.2% and 25.5%, respectively, and microorganism metabolism contributed 53.2% to NH 4 + -N removal. The novel texture structure of the carrier leads to improved mass transfer of nutrients and stable activity of microorganisms. Nitrification followed the first-order reaction for low concentration of effluents and zero-order reaction for high concentration of effluents. The reaction rate increased with increasing initial NH 4 + -N concentration. The magnetic carrier was applicable for a long time. These results show the great potential of the developed carrier for industrial applications.

Fiber-Optic Surface Plasmon Resonance Sensor for Trace Cadmium-Ion Detection Based on Ag-PVA/TiO2 Sensing Membrane

Ting Li,Wenlin Feng

Water-responsive actuators based on the solution casted PVA/epoxidized-SBS two-way shape memory bilayer composite film

Sijia Ren,Jiachun Feng

Water-responsive actuators have been of increasing interest in various applications. In this work, water-responsive actuators based on the bilayer composite film were prepared using commercialized PVA and SBS by a two-step solution casting method. In order to improve the adhesion between the PVA layer and SBS layer, SBS was firstly epoxidized to improve the polarity. Immediately after a thin film was formed on the surface of the epoxidized-SBS (E-SBS)/tetrahydrofuran solution, the PVA aqueous solution was poured onto the film and dried. It was found that the adhesive property between the two layers was improved and the adhesion strength reached 1005 kPa. The resultant bilayer film displayed the water-responsive two-way shape memory effect and exhibited excellent cyclic performance in five cycles. Flower-like and claw-like actuators based on the bilayer composite film were prepared and the actuation performance was demonstrated, suggesting their potential for applications in the fields of biomedicine and sensors.

High strength polyvinyl alcohol/polyacrylic acid (PVA/PAA) hydrogel fabricated by Cold-Drawn method for cartilage tissue substitutes

Yizhu Cheng,Yinchun Hu,Mengjie Xu,Miao Qin,Weiwei Lan,Di Huang,Yan Wei,Weiyi Chen

Poly (vinyl alcohol) (PVA) hydrogel has been considered as promising cartilage replacement materials due to its excellent characteristics such as high water content, low frictional behavior and excellent biocompatibility. However, lack of sufficient mechanical properties and cytocompatibility are two key obstacles for PVA hydrogel to be applied as cartilage substitutes. Herein, Polyacrylic acid (PAA) has been introduced into PVA hydrogel to balance these problems. Compared with pure PVA hydrogel, PVA/PAA hydrogel has the equal excellent biocompatibility, and its cell adhesion is significantly improved. In order to further improve the mechanical properties of hydrogels, Cold-Drawn treatment of hydrogels is performed in this paper. Compared to pure 12% PVA hydrogel, 40.8‐fold, 50.8‐fold, and 46.8‐fold increase in tensile strength, tensile modulus, and toughness, respectively, which can be obtained from 12% PVA/PAA Cold-Drawn hydrogel. These biocompatible composite hydrogels have a great application potential as cartilage tissue substitutes.

Facile Fabrication of Poly(vinyl alcohol)/Polyquaternium-10 (PVA/PQ-10) Anion Exchange Membrane with Semi-Interpenetrating Network

Zhaojie Yang,Minghua Zhang,Yafei Xiao,Xi Zhang,Minmin Fan

Anion exchange membranes (AEMs) are one of the core components of AEM fuel cells. A series of poly(vinyl alcohol)/polyquaternium-10 (PVA/PQ-10) AEMs with semi-interpenetrating networks (s-IPNs) are prepared by a simple solution-casting method using glutaraldehyde (GA) as a cross-linking agent. Subsequently, the prepared PVA/PQ-10 cross-linked membranes are characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, mechanical analysis, water uptake and swelling ratio tests, ion exchange capacity (IEC) tests, ionic conductivity measurements, and oxidative/alkaline stability tests. The effects of the mass ratio of PVA and PQ-10 and the amount of cross-linking agent GA on the performance of the PVA/PQ-10 cross-linked membranes are systematically explored. The results show that the cross-linked PVA/PQ-10 AEMs have high IEC and low water uptake and swelling ratio, and its maximum ionic conductivity can reach 79.37 mS cm –1 at 80 °C. In addition, the PVA/PQ-10 cross-linked membrane has good oxidative and alkaline stability under optimal preparation conditions. These results may provide valuable insights toward more effective scheme designs and new, simple preparation methods for AEMs with s-IPN structures.

Co7Fe3/CoFe2O4@C Lamellar composites derived from Co–Fe LDH/PVA as an effective heterogeneous activator of peroxymonosulfate

Yuanming Deng,Xi Zou,Zairan Liu,Jinzhi Wang,Zhong Wang,Jiaoning Tang

Here we present a simple method to prepare a highly efficient three components nanocomposites via thermal degradation of layered double metal hydroxides (LDHs)@polyvinyl alcohol (PVA) composites. Co 7 Fe 3 /CoFe 2 O 4 @C obtained from this method is applied to activate peroxymonosulfate (PMS) to degrade polluted organics and showed excellent performance. The best removal RhB efficiency of Co 7 Fe 3 /CoFe 2 O 4 @C (Co/Fe = 1:1) is near 100% within 10 min and the lowest ions elution (∼0.05 mg/L) under pH = 7, which is also better than the performance of the precursor Co–Fe LDH. Through further cycling experiments and degradation of p -nitrophenol, the stability and catalytic performance of the catalyst were verified. Finally, free radical scavenging experiments prove ·OH and SO 4 · - radicals participating in the reaction, which are the key factors for degradation. Based on the above, the derivation of the mechanism of Co 7 Fe 3 /CoFe 2 O 4 @C (Co/Fe = 1:1) catalyzing PMS to degrade polluted organics was proposed, and we consider this catalyst has great application prospect.