纳米纤维素的制备及其在包装中的应用研究

纤维素是地球上最丰富的可再生天然物质,纳米纤维素(Nanofibers cellulose,NFC)是从天然纤维素中提取出来的纳米级高分子材料,具有优良的机械性能、光学性能和生物降解性能。本文综述了国内外纳米纤维素的制备方法,总结了纳米纤维素作为一种新型环保材料在包装行业中的应用。     

纤维素基吸附功能材料的应用及其发展趋势

纤维素是一种来源广泛的天然生物高分子,拥有棉、麻及醋酸菌荚膜等多种原材料来源,具有良好的生物友好性、可生物降解性及良好的力学强度等。纤维素基功能材料是指利用纤维素,通过生物、化学以及物理等方法制造的一类新材料。结合国内外纤维素基吸附材料的研究现状,介绍了多种纤维素基吸附功能材料的状况及今后发展态势。     

细菌纤维素模板合成研究进展

细菌纤维素是一种新型的天然纳米生物材料,具有独特的物理、化学和机械性能,并具有较高的生物活性、良好的生物相容性和生物可降解性.以细菌纤维素为模板,可利用其三维网络结构和纳米级孔径分布来控制合成具有预期特定形貌与尺寸的纳米材料,从而获得各种新的功能材料.综述了目前以细菌纤维素为模板的合成研究进展.     

纤维素基可生物降解共混高分子材料的制备和性能

综述了近年来以纤维素为共混组分制备可生物降解高分子材料的研究进展,重点介绍了纤维素或纤维素衍生物与其它天然高分子(壳聚糖、蛋白质、淀粉等)以及可降解合成高分子(聚乙二醇、聚己内酯、聚乳酸等)共混材料的制备和性能,揭示了纤维素基可生物降解材料在某些应用领域替代石油基材料的潜力.     

天然高分子可降解材料的研究与发展

重点介绍了几种常见的天然高分子可降解材料(纤维素、木质素、淀粉、甲壳素和壳聚糖、蛋白质)的研究进展,并对其应用前景作了展望.     

纤维素基可降解抑菌食品包装材料的研究及应用进展

目的 对纤维素在抑菌食品包装领域的研究进行综述,分析纤维素在抑菌材料中的作用和抑菌效果.方法 归纳近几年国内外基于纤维素、纤维素衍生物以及纳米纤维素的抑菌包装材料的制备方法和抑菌效果,对纤维素基可降解抑菌食品包装的发展方向提出展望.结果 天然高分子纤维素具有优异的生物兼容性、可降解性、可再生性、无毒性等特点,已成为开发现代食品包装材料的重要资源;制备的纤维素基食品包装材料具有优异的力学性能和显著的抑菌效果,且降低了传统化石包装材料有害物质对食品安全的潜在影响.结论 纤维素基食品包装材料有望取代化石包装材料,最大程度地保障食品质量与安全,是现代食品包装产业的发展方向,具有较大前景.     

基于离子液体溶解-超临界干燥技术制备纤维素基气凝胶材料的研究进展

作为自然界储量最为丰富、可持续、可再生、环境友好的一种天然原材料,纤维素已成为高分子材料领域的研究热点之一。其中纤维素气凝胶兼具超高孔隙率、超低密度纳米多孔材料的优点和高分子材料韧性好、易加工的特性,有诸多优异的性能,是继无机气凝胶和合成高分子气凝胶之后新一代气凝胶材料,正受到人们广泛的关注。介绍了作者课题组利用离子液体制备纤维素气凝胶方面的研究进展,主要包括:利用离子液体溶解结合超临界CO_2干燥技术制备纤维素气凝胶;纤维素基复合气凝胶材料的制备;以及纤维素气凝胶材料作为锂离子电池凝胶聚合物电解质的应用。     

基于改性纳米纤维素的电化学储能材料的研究进展

纤维素是一种来源广泛、绿色友好的天然高分子材料。由各种物理化学手段从纤维素中提取出来的纳米纤维素(NC)拥有提取简单、高结晶度和高比表面积等优点，将其用于与其他材料复合时往往能激发出复合材料更大的潜力。基于纳米纤维素表面暴露出的大量羟基结构可以对其进行功能化改性，这对于进一步发挥纳米纤维素的潜力具有重大的意义。简要介绍了纳米纤维素的改性方法以及在电化学储能领域中的应用和展望。     

纳米纤维素的应用研究进展

纳米纤维素是一种新型的天然高分子材料,具有高结晶度、高强度等特殊的理化性质和优良的机械性能,其应用范围将越来越广泛。主要综述了纳米纤维素在酶固定化、生物传感、生物成像、医药及造纸工业等方面的应用,并对其发展前景进行了展望。     

纳米科技在水产加工上的应用（二）

◆纳米甲壳素甲壳素是自然界中唯一带正电荷的天然高分子材料，是一种天然碱性多糖，是仅次于纤维素的第二大糖类，广泛地应用于生物医学、保健、环保、食品等领域，随着其“纳米化”后，更扩大了应用范围，提高了功效。     

基于无机填料复合薄膜的摩擦纳米发电机研究进展

摩擦纳米发电机(Triboelectric Nanogenerator, TENG)是一种将微小机械能转化为电能并加以收集利用的绿色能源器件, 具有活性材料种类广泛、器件结构简单以及易于集成等特点。较低的输出功率密度是目前阻碍其实际应用的主要因素之一。如何通过材料组分设计与制备提高其输出功率密度及能量转化效率, 是目前该领域研究者关注的热点问题。在摩擦纳米发电机常用的活性材料-高分子聚合物中引入功能性填料是一种简便且高效的改性方法, 不仅能够对薄膜摩擦电性能进行优化、提高输出性能, 还能够赋予其新功能, 可谓一举多得。因此, 此类复合薄膜已广泛应用于TENG领域, 例如TiO₂、SiO₂、BaTiO₃、ZnSnO₃、MoS₂、石墨烯、二维黑磷等无机填料对复合材料的性能均有不同程度的优化, TENG的输出功率密度最高提升了数十倍。本文结合国内外研究现状, 按照填料对基体材料表面性能以及电学性能优化作用两个方面进行阐述, 综述了复合材料薄膜在摩擦纳米发电机中的研究进展, 并展望了未来复合材料用于提高TENG输出性能研究的发展方向。     

Multilayered flexible nanocomposite for hybrid nanogenerator enabled by conjunction of piezoelectricity and triboelectricity

We fabricate a flexible hybrid nanogenerator (HNG),based on multilayered nanocomposite materials,which integrates a piezoelectric nanogenerator (PENG) and a triboelectric nanogenerator (TENG) into a single structure with only two electrodes.The HNG enables enhancement of the electrical output of the nanogenerators.An open-circuit voltage of 280 V and a short-circuit current of 25 μA are achieved by a HNG of 2.5 cmx 2.5 cm in size,superior to the performance of previously reported HNGs.In addition,the energy-conversion process of the HNG relies on the working mechanism of both the PENG and TENG.The polarization direction and doping content of BTO are the two major factors that affect the electrical output.Biomechanical energy harvesting from walking motion or the bending of an arm is also demonstrated.     

Charge storage coating based triboelectric nanogenerator and its applications in self-powered anticorrosion and antifouling

As a novel energy-harvesting device, a triboelectric nanogenerator (TENG) can harvest almost all mechanical energy and transform it into electrical energy, but its output is low. Although the micro-nano structures of triboelectrode surfaces can improve their output efficiency, they lead to high costs and are not suitable for large-scale applications. To address this problem, we developed a novel TENG coating with charge-storage properties. In this study, we modified an acrylic resin, a friction material, with nano-BaTiO₃ particles and gas phase fluorination. The charge-trapping ability of nanoparticles was used to improve the output of TENG. The short-circuit current and the output voltage of coating-based TENGs featuring charge storage and electrification reached 15 μA and 800 V, respectively, without decay for longtime working. On this basis, self-powered anticorrosion and antifouling systems are designed to reduce the open circuit potential of A3 steel by 510 mV and reduce the adhesion rate of algae on the surface of metal materials. This study presents a high-output, stable, coating-based TENG with potential in practical applications for anticorrosion and antifouling.     

Transparent paper-based triboelectric nanogenerator as a page mark and anti-theft sensor

The triboelectric nanogenerator （TENG）, based on the well-known triboelectric effect and electrostatic induction effect, has been proven to be a simple, cost effective approach for self-powered systems to convert ambient mechanical energy into electricity. We report a flexible and transparent paper-based triboelectric nanogenerator （PTENG） consisting of an indium tin oxide （ITO） film and a polyethylene terephthalate （PET） film as the triboelectric surfaces, which not only acts as an energy supply but also as a self-powered active sensor. It can harvest kinetic energy when the sheets of paper come into contact, bend or slide relative to one another by a combination of vertical contact-separation mode and lateral sliding mode. In addition, we also integrate grating-structured PTENGs into a book as a self-powered anti-theft sensor. The mechanical agitation during handling the book pages can be effectively converted into an electrical output to either drive a commercial electronic device or trigger a warning buzzer. Furthermore, different grating-structures on each page produce different numbers of output peaks by sliding relative to one another, which can accurately act as a page mark and record the number of pages turned. This work is a significant step forward in self-powered paper-based devices.     

A Metal-Like Conductive Elastomer with a Hierarchical Wrinkled Structure

For the development of wearable electronics, the replacement of rigid, metallic components with fully elastomeric materials is crucial. However, current elastomeric electrodes suffer from low electrical conductivity and poor electrical stability. Herein, a metal-like conductive elastomer with exceptional electrical performance and stability is presented, which is used to fabricate fully elastomeric electronics. The key feature of this material is its wrinkled structure, which is induced by in situ cooperation of solvent swelling and densely packed nanoparticle assembly. Specifically, layer-by-layer assembly of metal nanoparticles and small-molecule linkers on elastomers generates the hierarchical wrinkled elastomer. The elastomer demonstrates remarkable electrical conductivity (170 000 and 11 000 S cm⁻¹ at 0% and 100% strain, respectively), outperforming previously reported elastomeric electrodes based on nanomaterials. Furthermore, a fully elastomeric triboelectric nanogenerator based on wrinkled elastomeric electrode exhibits excellent electric power generation performance due to the compressible, large contact area of the wrinkled surface during periodic contact and separation.     

基于石墨烯森林电极的摩擦纳米发电机

本研究提出并制备了一种以石墨烯森林为电极的摩擦纳米发电机。利用等离子体增强化学气相沉积工艺制备了与其它墙形竖直薄片状的石墨烯形貌差异较大的石墨烯森林。此石墨烯森林具有低薄膜电阻((110±5) Ω/□)以及独特的离散“树状”结构, 有利于石墨烯森林与其他电极材料之间的接触和摩擦。根据石墨烯森林的形貌优势, 将聚酰亚胺膜和石墨烯森林膜作为电极组装摩擦纳米发电机, 其开路电压可达20 V, 短路电流可达0.75 μA。此外, 还讨论了基于石墨烯森林的摩擦纳米发电机的工作原理。最后, 利用此纳米发电机点亮了演示电路中三个不同颜色的LED, 证明了石墨烯森林在摩擦纳米发电机中的有效应用。     

基于纳米材料与纳米结构的纳米电源研究进展

随着现代社会的发展和能源危机的来临, 探索和寻找新的能源材料, 开发新能源是人类的永恒课题。自2006年基于ZnO纳米线压电效应的压电式纳米电源问世以来, 又研制出多种基于纳米材料和纳米结构, 以及不同纳米效应的新型纳米电源。本文综述了近10年来, 人们在纳米电源领域的研究成果; 系统介绍了基于压电效应、摩擦效应以及石墨烯能带调控纳米电源的原理和特点, 为今后新型纳米电源的开发提供思路和参考。     

压电式纳米发电机及其混合器件的研究进展

随着化石能源的过度使用和开采,随之而来的能源和环境问题也日益尖锐,而人们对能源的需求不减反增,因此寻求一种新型的绿色可持续能源是非常必要的。环境中的能量十分丰富,因此从环境中收集能量进行转化是十分有前景的方法。压电材料在受到外界作用发生机械变形时,能实现机械能向电能的转化,因此,压电式纳米发电机作为一种潜在的可持续、绿色能源,近年来受到广泛关注。从压电材料的分类入手,结合其制备方法、结构和性能等,对近年来一些研究成果进行了概述,详细评价了不同制备方法、结构对压电式纳米发电机压电性能的影响,并对今后发展进行了展望。     

Water wave energy harvesting and self-powered liquid-surface fluctuation sensing based on bionic-jellyfish triboelectric nanogenerator

Due to the natural working mechanism of triboelectric nanogenerators (TENGs), potential energy stored by elastic materials may not be effectively converted into electric power, post mechanical triggering. Here, we report a practical bionic-jellyfish triboelectric nanogenerator (bjTENG) with polymeric thin film as the triboelectric material, which is shape-adaptive, with a hermetic package and a unique elastic resilience structure, similar to the behavior of a jellyfish. The charge separation in the elastic resilience of this bionic-structure is based on the liquid pressure-induced contact-separation of the triboelectric layers. On the basis of the conjunction of the triboelectrification and the electrostatic induction, a sustainable and enhanced output performance of 143?V, 11.8?mA/m² and 22.1?μC/m² under a low frequency of 0.75?Hz and at a water depth of 60?cm is produced, which can be used to supply power for dozens of green LEDs or a temperature sensor directly. More significantly, bjTENG is believed to be a priority technology which is attributable to its highly sensitivity, portability, and suitability for continuous detection of water level and fluctuation. Furthermore, a wireless self-powered fluctuation sensor early-warning system, which provides exact and wireless monitoring of fluctuation of a liquid surface, is also successfully developed.     

Single‐Step Fluorocarbon Plasma Treatment‐Induced Wrinkle Structure for High‐Performance Triboelectric Nanogenerator

A triboelectric nanogenerator (TENG) has been thought to be a promising method to harvest energy from environment. To date, the utilization of surface structure and material modification has been considered the most effective way to increase its performance. In this work, a wrinkle structure based high‐performance TENG is presented. Using the fluorocarbon plasma treatment method, material modification and surface structure are introduced in one step. The output ability of TENG is dramatically enhanced. After the optimization of plasma treatment, the maximum current and surface charge density are 182 μA about 165 μC m^?2. Compared with untreated TENG, the wrinkle structure makes the current and surface charge density increase by 810% and 528%, separately. X‐ray photoelectron spectroscopy is employed to analyze the chemical modification mechanism of this fluorocarbon plasma treatment. Facilitated by its high output performance, this device could directly light 76 blue light emitting diodes under finger typing. The output electric energy could be stored then utilized to power a commercial calculator. As a result of the simple fabrication process and high output ability, devices fabricated using this method could bring forward practical applications using TENGs as power sources.