查找使用阿拉丁产品的科研文献

Enhanced performance triboelectric nanogenerator based on mullite/PVA composites for self-driven sensing and smart home control

Ping Zhang,Yuting Ma,Baocheng Liu,Honghao Zhang

Polyvinyl alcohol (PVA) has good biocompatibility, a simple fabrication process, and environmental protection, which is very suitable for the production of triboelectric nanogenerator (TENG) applied to smart home control. However, the output performance of the TENG composed of PVA and PDMS films is not high. Previous research has explored the enhancement of PVA-based TENG performance by doping with conductive materials to modify the dielectric properties of PVA composite films. Nevertheless, this approach is associated with issues of high production costs and energy consumption. This work prepared a mullite/PVA composite material TENG (MP-TENG), the introduction of mullite induced interfacial polarization in the composite film. This effect resulted in the appearance of polarization centers, thereby enhancing the charge-sensing capability of the composite film. Consequently, the triboelectric output performance of the MP-TENG was improved. MP-TENGs with different amounts of mullite fiber doping were prepared, and the maximum output performance was obtained when the doping level reached 3 wt%. At this concentration, the composite film exhibited an open-circuit voltage of 70.89 V and a short-circuit current of 2.45 μA. An enhancement of 1.78 and 1.71 times was achieved with respect to the pure PVA-TENG, respectively. In addition, MP-TENG exhibited excellent sensing characteristics, a smart home control system was designed in conjunction with a hardware circuit, which captured hand motions and encoded them to generate binary codes to control the on/off state of the indoor home.

High performances of dual network PVA hydrogel modified by PVP using borax as the structure-forming accelerator

Min Huang,Yi Hou,Yubao Li,Danqing Wang,Li Zhang

One-step approach to fabrication of PDA-PVA coatings with outstanding antifogging performance assisted by light illumination

Xiuxian Gu,Junhui He

Using clean and renewable solar energy, photothermal technology has garnered significant attention from researchers. Photothermal materials possess the capability to efficiently convert solar energy into thermal energy. In this work, polydopamine (PDA)- poly (vinyl alcohol) (PVA) coatings with outstanding antifogging performance assisted by light illumination were fabricated by a one-step scrape coating method at room temperature. PDA with excellent photothermal properties and strong adhesion to substrate was applied in combination with PVA as matrix. Carbon dots (CDs), which had previously been found as nano-crosslinkers to form abundant hydrogen bonds with hydroxyl groups of PVA and substrate, was used to enhance the mechanical robustness and the adhesion to substrate of coatings, producing a synergistic effect with the PDA. The coatings had an average transmittance exceeding 80 % in the visible region. Under xenon lamp with light intensities of 60, 80 and 100 mW cm −2 at the coating location, the temperature of the coating surface rose to 40.2, 46.1 and 53.1℃, respectively. Under xenon lamp with a light intensity of 100 mW cm −2 at the coating location, the antifogging duration when exposed to hot steam 5 cm above a 60 °C water bath was three times more than that without xenon lamp illumination. The coating remained unaffected even after immersion in water and various solvents for 2 h, without showing any signs of folding or damage. The coating exhibited a pencil hardness of up to 8 H and adhesion-to-substrate of up to 5 A, and was able to withstand the Taber wear test for 4000 cycles. The preparation method is simple and efficient, and may be applicable to a wide range of optical, optoelectronic, medical scenarios.

Negative Swelling and Mechanical Self-Enhancement TAFe@PVA Photothermal Hydrogel Mediated Via Semi-Crystallization for Medical Implants

Qingrong Zhang,Sicen He,Ailian Mei,Wei Xia,Yunchang Cao,Zeying Zhang,Jiezhi Jia,Jiacai Yang,Jiangfeng Li,Gaoxing Luo,Zheng Li

Medical implants, important consumables, significantly promote patients’ healthcare, but still face challenges of foreign body responses and bacterial infection. Hydrogels can be ideal alternative materials, however, a few of them can meet the requirements. Herein, a TAFe@PVA photothermal hydrogel integrating with negative swelling, long-term stability, antibacterial, anti-adhesion, and tissue mechanical matching is developed to solve these issues. The TAFe@PVA hydrogel is crosslinked by H-bonds and microcrystal domains which both can be enhanced by cations or anions based on Hofmeister effect, showing unique negative swelling and long-term mechanical self-enhancement performances in the physiological fluid. Attributing to self-polymerization of tannic acid (TA) and negative swelling of polyvinyl alcohol (PVA) molecular networks, TAFe complexes can be strongly locked in PVA molecular networks, reaching long-term photothermal stability. The TAFe@PVA hydrogel also exhibits great biocompatibility, anti-oxidation, anti-adhesion, and anti-bacterial performances, comparing to the traditional implant material. Since the TAFe@PVA hydrogel can better match with skin tissues, fewer macrophages and myofibroblasts are activated, which depresses unexpected foreign body responses. Finally, the TAFe@PVA hydrogel as the implant can effectively solve abdominal adhesions after abdominal operation and promote defects healing. This study introduces a promising hydrogel implant, which potentially extends hydrogels to wider medical applications.

Non-covalently Functionalized Graphene Oxide-Based Coating to Enhance Thermal Stability and Flame Retardancy of PVA Film

Chen Wenhua,Liu Pengju,Min Lizhen,Zhou Yiming,Liu Yuan,Wang Qi,Duan Wenfeng

The synergistic effect of conventional flame-retardant elements and graphene has received extensive attention in the development of a new class of flame retardants. Compared to covalent modification, the non-covalent strategy is simpler and expeditious and entirely preserves the original quality of graphene. Thus, non-covalently functionalized graphene oxide (FGO) with a phosphorus–nitrogen compound was successfully prepared via a one-pot process in this study. Polyethyleneimine and FGO were alternatively deposited on the surface of a poly(vinyl alcohol) (PVA) film via layer-by-layer assembly driven by electrostatic interaction, imparting excellent flame retardancy to the coated PVA film. The multilayer FGO-based coating formed a protective shield encapsulating the PVA matrix, effectively blocking the transfer of heat and mass during combustion. The coated PVA has a higher initial decomposition temperature of about 260 °C and a nearly 60% reduction in total heat release than neat PVA does. Our results may have a promising prospect for flame-retardant polymers.

Chitosan/PVA composite film enhanced by ZnO/lignin with high-strength and antibacterial properties for food packaging

Xinxin Zhang,Gang Li,Chen Chen,Hongxian Fan,Jing Fang,Xingjiang Wu,Junjie Qi,Hao Li

This study aims to develop a chitosan/polyvinyl alcohol (CS/PVA) composite film (QZCS/PVA) for food packaging, enhanced by the incorporation of quaternary ammonium lignin/ZnO nanoparticles (QAL/ZnO) to improve its antibacterial, antioxidant, and mechanical properties. The QAL/ZnO nanoparticles were synthesized using a co-precipitation method, resulting in a synergistic effect that enhances the uniformity and stability of the composite film. The double cross-linked CS/PVA composite film containing QAL/ZnO nanoparticles effectively mitigates the brittleness of pure chitosan films, achieving a tensile strength of 95.89 MPa. Crucially, the inclusion of QAL/ZnO imparts exceptional antioxidant and antibacterial properties to the QZCS/PVA composite film. Disk diffusion assays revealed markedly enhanced antibacterial efficacy against Staphylococcus aureus and Escherichia coli in comparison to analogous biopolymer films. The dense network structure of the composite film also provides excellent water resistance, which contributes to extending the shelf life of food products. In a 12-day grape preservation experiment, the composite film exhibited outstanding preservation performance. These results underscore the potential of the CS/PVA composite film containing lignin and chitosan for food packaging applications, offering significant advantages in improving food preservation.

AA grafted PVA/CMC interpenetrating network gel polymer electrolyte for quasi-solid-state zinc ion hybrid supercapacitor

Yongtao Tan,Mei Xi,Yuan Zhang,Zhengda Qiao

Polymer gel electrolyte is a topic for a storage energy device. This work focuses on the double interpenetrating network polymer of polyvinyl alcohol/carboxymethyl cellulose (PVA/CMC) to graft acrylic acid (AA) and combine ZnCl 2 to form multi-polymer network gel electrolyte for zinc ion supercapacitors. The assembled zinc ion supercapacitors of commercial activated carbon (YP50)//Zn with multi-polymer network gel electrolyte exhibit higher specific capacitance of 272 F g −1 at a current density of 0.25 A g −1 than the device with polyvinyl alcohol/polyacrylic acid (PVA/PAA) or PVA electrolyte. In addition, the zinc ion supercapacitor can achieve a maximum energy density of 151.2 Wh kg −1 , higher than traditional electrical double layer supercapacitor YP50//YP50 device. Further, the device can work under different temperatures from −20∼60 °C, which can meet the requirements of some outdoor activities for energy storage devices.

A hydrophobic graft-modified PVA hydrogel by michael addition joint with gelation strategy for underwater cardiac sensing

Yuefei Ding,Yufei Shi,Hengyi Cheng,Dan Yu,Wei Wang

The rapid development of global big health and AI technology has made electrocardiogram (ECG) monitoring in all scenarios more important. While real-time ECG monitoring in the air is easy to realize, underwater ECG monitoring is still challenging for general hydrogels. Herein, we prepared a hydrogel with underwater viscosity , biocompatibility, and excellent mechanical properties by hydrophobic graft-modified of PVA (POV) hydrogel and used it to prepare electrodes for underwater ECG monitoring. The POV hydrogel is very flexible and co-deforms easily with the skin, with a Young's modulus as low as 0.03 MPa and underwater adhesion strength up to 11 KPa. The hydrophobic chain segments within the POV hydrogel give the hydrophobic gel excellent stability, adhesion, and ionic conductivity given by the free ionic groups within the POV hydrogel enable the POV hydrogel to detect and transmit physiological electrical signals. Compared to commercial gel electrodes, this POV electrode has better adhesion, conductivity and stability underwater. The POV gel electrodes can effectively collect real-time ECG signals in the air and underwater. Therefore, this study effectively broaden the application of POV hydrogels in ECG biosensors for underwater cardiac sensing.

Preparation of DCNC chemically cross-linked CMC/PVA composite film for sustainable and strawberry preservation active packaging

Xue Fu,Shuyan Xu,Mingyu Ma

In recent years, with the increasing attention to food safety and environmental protection, the development of biodegradable food packaging materials with comprehensive performance has become a hotspot. This article presents the preparation of a polyvinyl alcohol carboxymethyl cellulose composite film with barrier property. This study utilized formaldehyde nanocellulose as a crosslinking agent to chemically modify composite membranes. Further promote its application in food preservation. The mechanical properties and barrier properties of formaldehyde cellulose (DCNC) polyvinyl alcohol (PVA) carboxymethyl cellulose (CMC) composite films were studied. Apply the prepared DCNC/PVA/CMC composite film to strawberry preservation experiments. The results showed that cross linked modified composite film can more effectively reduce indicators such as weight loss rate, titratable acid content and ascorbic acid content of strawberries, thus effectively prolonging strawberry shelf life by 4 days. This indicates that modified composite films have certain potential application value in the field of food packaging.

PVA/PAAm hydrogel-on-titanium alloy with high bonding strength and low friction as articular cartilage replacement

Liu Jia,Shi Yan,Li Bo,Li Jianliang,Shao Jiaojing,Li Long,Liu Qibin,Cao Lulu

Tough bonding and low friction are required for the candidate artificial articular cartilage materials. Inspired by the soft-on-hard composite structure of natural cartilage, polyvinyl alcohol/polyacrylamide (PVA/PAAm) hydrogel-on-titanium alloy was prepared by a casting-drying method to combine the excellent lubrication of soft hydrogel and the high load-bearing capacity of rigid substrate. The influences of PVA: PAAm mass ratio and swelling on the interfacial toughness of PVA/PAAm hydrogel-on-titanium alloy were evaluated by the 90° peeling test, and the friction property was investigated as a function of PVA: PAAm mass ratio, lubricating medium, and load. The results show that the interfacial toughness of PVA/PAAm hydrogel-on-titanium alloy ranges from 150 N m −1 to 400 N m −1 in dry state, while the interfacial toughness decreases significantly after swelling in deionized water for 24 h. The friction coefficient of PVA/PAAm hydrogel-on-Ti6Al4V alloy is ~ 0.15 when PVA: PAAm mass ratio is 1:2 under fetal bovine serum lubricating. The polyvinyl alcohol/polyacrylamide (PVA/PAAm) hydrogel-on-titanium alloy configuration provide a new strategy for the design of soft-on-hard cartilage replacement with tough bonding and low friction.

Fabrication of multifunctional sodium alginate aerogel enhanced by in situ dual crosslinking with PVA and Zn2 + /Al3+

Jun Yang,Yihua Xu,Bingqing Fu,Hongyan Li,Fangtao Xiong,Huifang Zhao,Lizheng Sha,Yinchao Xu,Daliang Guo,Jing Li

In order to address the urgent demand for sustainable thermal insulation materials, a biomass-based sodium alginate (SA) aerogel was developed through in situ dual crosslinking with polyvinyl alcohol (PVA) and Zn 2+ /Al 3+ in this work. The SAP-Al 0.15 aerogel demonstrated exceptional multifunctionality with ultra-low density (2.37 ×10 −2 g·cm −3 ), excellent mechanical strength (366.2 kPa longitudinal, 846.7 kPa transverse), and superior flame retardancy (LOI=30.4 % and UL-94 V-0 rating). Hierarchical pore architecture enabled remarkable thermal insulation (ΔT = 55 ℃ at 80 ℃ heating) and weight-bearing capacity (over 3300 times of self-weight). Systematic characterization revealed that Al³ ⁺ crosslinking preferentially enhanced network densification through strong carboxyl coordination, achieving 35.4 % char residue with protective Al 2 O 3 layers. Compared to SAP-Zn 0.15 , Al 3+ crosslinking increased compressive modulus by 377 % while maintaining 97.6 % porosity. This EDTA-mediated in situ dual crosslinking strategy successfully resolved the mechanical-thermal-flame retardancy comprehen-sive improvement in biomass aerogels, positioning SAP-Al 0.15 as an eco-friendly alternative to conventional insulation foams for architectural heat insulation. This work provided fundamental insights into the structure-property relationships of biopolymer-based aerogels, offering a sustainable materials platform for energy-efficient building applications.

Preparation and performance optimization of PVP/PVA coatings with high adhesion and high hydrophilicity for coronary guidewires

Longxiang Qian,Hao Xu,Yiwei Lu,Zezhong Chen

In response to the adverse events caused by the detachment of coatings during coronary guidewire interventions, this research investigates and optimizes the preparation process of a polyvinyl alcohol (PVA)/polyvinylpyrrolidone (PVP) coating with high adhesion and hydrophilicity. Using thermoplastic polyurethane (TPU) as the substrate, the coating was prepared via polydopamine (PDA) deposition and UV curing technology. The amounts of PVA, PVP, and polyethylene glycol diacrylate (PEGDA), as well as the proportion of the photoinitiator, were optimized through orthogonal experiments, significantly enhancing the hydrophilicity and adhesion of the coating. The optimized hydrophilic coating achieves a minimum water contact angle of 7.4°. The coating with the optimized formulation has a water contact angle of 12.2°, reaches grade 0 adhesion in the cross-cut test, and maintains a stable friction coefficient of 0.16. After water exposure, the water contact angle was 22.6°, and the friction coefficient remained below 0.2. Cytotoxicity tests showed cell viability between 90 % and 110 %, and the hemolysis rate was less than 5 %. These results indicate that the coating exhibits excellent hydrophilicity, adhesion, water resistance, and stability, offering significant potential to improve the safety and operability of coronary interventional guidewires, reduce coating-related adverse events, and enhance surgical quality and safety.