Controllable preparation of vertically standing graphene sheets and their wettability and supercapacitive properties

Vertically standing graphene(VSG) sheets have been fabricated by using plasma enhanced chemical vapor deposition(PECVD) method.The lateral size of VSG nanosheets could be well controlled by varying the substrate temperature.The higher temperature usually gives rise to a smaller sheet size.The wettability of VSG films was tuned between hydrophobicity and hydrophilicity by means of oxygen and hydrogen plasma treatment.The supercapacitor electrode made of VSG sheets exhibited an ideal double-layer-capacitor feature and the specific capacitance reached a value up to 9.62 F·m~(-2).     

纤维素微孔锂电隔膜的制备及性能研究

为了改善锂电隔膜的亲液性和耐高温性,以醋酸纤维素为成膜材料,利用相转化法制备了新型锂电隔膜,通过形貌和孔道结构表征、亲液性能和耐热性能测试对醋酸纤维素隔膜的基本性能进行研究,并将该隔膜装配成锂离子电池进行充放电性能测试. 结果表明,醋酸纤维素隔膜具有均匀的微孔结构,孔隙率达到65%,约为传统聚烯烃隔膜的1.5倍;纤维素材料的良好亲液性和高孔隙率结构改善了隔膜的吸液性能,其吸液率达到285%;该隔膜在150 ^oC、30 min的热处理条件下未发生明显的热收缩. 鉴于上述优点,相对于市售PE隔膜,醋酸纤维素隔膜所装配锂离子电池显示出更优的循环性能和倍率性能.     

Using Plasma-Activated High Performance Fibers with Nanocrystalline Structure in Producing New Reinforced Composite Materials

A multifilament wet-pull-out method for estimation of physicochemical interaction between the fiber and the matrix in composite materials reinforced with high-strength high-modulus polyethylene fiber has been proposed. Controlled parameters are fiber capillary rise h and pull-out force F. The method allows one to estimate the wettability and multifilament fiber impregnation with the liquid matrix and measure fiber capillary rise and the joint strength after curing process finished. The multifilament wet-pull-out method considers a total interaction between the matrix and filaments in a complex fiber or yarn. It is the advantage of this method in comparison with the tests of individual monofilament. The method makes it possible to model the real operating conditions of CM.     

固液润湿性对流体动压润滑薄膜的影响

利用自行开发的微型面接触润滑油膜测量系统,研究了固液润湿性对流体动压润滑油膜厚度的影响.试验中以静止的微型滑块平面和旋转的光学透明圆盘平面形成润滑副.固液的润湿性通过接触角判定,不同材料的微滑块平面和润滑液体形成不同的界面.在保持载荷和面接触楔形角不变的条件下对油膜厚度-速度关系进行了测量.结果表明:对于固液润湿性强的界面,形成的油膜厚度与经典润滑理论有较好的一致性;当固液润湿性明显降低时,测量得到的油膜厚度减小.对于试验中观察到的界面效应,应用界面滑移理论进行了初步分析.     

仿生制备功能性聚合物光子晶体

简述了自然界生物光子晶体经过不断的进化与演变而具有的一些特殊的性能,如亮丽的结构色彩、特殊的浸润性及高强度.受自然界生物光子晶体的这些特殊性能启发,通过对聚合物乳胶粒硬核软壳结构、表面功能基团及表面形貌的设计和调控等方法仿生制备了具有特殊浸润性的光子晶体;并在胶体晶体的聚合物乳胶粒间引入光交联聚合物,制备得到高强度的光子晶体;通过对蘑菇头形状乳胶粒两端的浸润性差异的设计制备,组装得到新型的各向异性结构的光子晶体.进一步发展了这些功能性光子晶体在湿度检测、油传感、自振荡体系等方面的应用.发展了通过喷涂、打印方法实现大面积、图案化聚合物光子晶体的简单制备.     

特殊润湿性油水分离材料的开发与研究

随着工业的发展,油水污染日渐严重,特别是石油的泄露、有机化学品的排放对生态环境造成了难以挽救的损害。因此,开发新型高效的油水分离材料与技术是一个极为重要的任务。特殊润湿性油水分离材料的出现,为科研人员指明了道路。本文以用于油水分离的特殊润湿性材料为研究体系;首先,对具有特殊润湿性油水分离材料的基本理论和设计理念进行分析;然后介绍了通过调控材料表面的微观结构和表面化学组成制备特殊润湿性材料实现不同的油水分离效果的研究进展,并且尝试从微纳米尺度上揭示特殊润湿性材料的特征,形成从微纳米尺度上揭示油水分离用材料化学品结构特征的技术基础。最后指出了目前在油水分离用功能材料化学品这一领域存在的一些问题,并对这一领域的发展趋势进行展望。     

液滴撞击具有浸润性分布的倾斜固壁铺展行为的格子Boltzmann研究

采用基于单组分多相伪势模型的格子Boltzmann方法,模拟了三维液滴撞击左右两侧浸润性不同的倾斜固壁的铺展过程,获得了液滴在壁面两侧的铺展因子、相对铺展宽度、相对高度和液滴运动速度随时间的变化情况,研究了壁面浸润性分布和壁面倾斜角度对液滴铺展过程的影响．结果表明,液滴在倾斜壁面的铺展过程受到重力和表面力的综合作用,重力影响液滴的铺展和沿壁面向下的滑动,壁面浸润性分布影响液滴向壁面亲水侧横向移动．     

A comparative study of different nanoclay-reinforced cellulose nanofibril biocomposites with enhanced thermal and mechanical properties

The objective of this research was to comprehensively compare the effects of nanoclay bentonite (BT), halloysite nanotubes (HNTs) and sulfuric acid-etched halloysite nanotubes on the surface wettability, morphological, mechanical and thermal properties of cellulose nanofibril (CNF) biocomposites. A simple and environmental safe casting-evaporation method was used to fabricate these samples, which comprised up to 10 wt% of nanoclay. The surface wettability, tensile testing and TG results showed that the biocomposites with BT exhibited greater hydrophobicity, larger modulus and strength and better thermal stability than with HNTs at low content. However, at high content, the biocomposites with HNTs exhibited larger elongation at break. The DMA results indicated that biocomposites with HNTs exhibited better molecular motion restriction than with BT. These results combined with Fourier Transform Infrared (FTIR) also indicated interfacial interactions between CNF matrix and nanoclay. Acid treatment would help promote the interfacial interactions between HNTs and CNFs, resulting in enhanced mechanical and thermal properties. This comparative study will help in the choice of appropriate nanoclay for use in functional biomaterials in industrial production applications.