无机分级纳米结构/疏水聚合物复合介电材料表界面构筑及其性能协同增强机理

Electrowetting-on-dielectric (EWOD) technology has a great application prospect in microfluidic chips, optical devices and reflective display devices. The fast development requires a novel dielectric material with high dielectric constant (ε) and excellent hydrophobic properties. The self-limitation of single-component dielectric material cause to involve the problem of the balance between high ε and hydrophobic properties by the compound approach. The previous works show that the hierarchical nanostructure/polymer composite exhibit the advantage in improving the ε and hydrophobic properties due to the surface-interface effect. Based on these studies, this project puts forward the new design method that hierarchical nanostructure was introduced into hydrophobic dielectric polymer. Hydrophobic polymer composite with different hierarchical interface and nano-rough surface is constructed by the design and synthesis of hierarchical nanostructures of TiO2 (TiO2/C). The effects of hierarchical nanostructure evolution, surface modification, polymer chain structure on the surface-interface structure, interfacial Interaction and dielectric-hydrophobic properties of composites will be studied intensively. The internal relationship among hierarchical nanostructure, surface-interface characteristic and hydrophobic-dielectric properties will be established. Polarization and dielectric-hydrophobic synergistic enhancement mechanism of composite material will be clarified. The completion of the research will provide new way and theoretical support for dielectric material for Electrowetting-on-dielectric (EWOD) technology.

介电润湿技术是发展微流控芯片、反射式显示和微流体光器件的关键，其快速发展迫切需要一种具有高介电常数(ε)和优异疏水特性的新型介电材料。单一组成介电材料自身的局限性诱发了通过复合的思路来解决二者难以兼顾的问题。前期初步研究发现：分级纳米结构与聚合物构建的表界面在提升ε和疏水特性方面有独特优势。基于此，本项目提出将无机分级纳米结构引入疏水聚合物的新设计思路，从设计、合成分级纳米结构TiO2(TiO2/C)入手，构筑具有分级结构界面和纳米级粗糙表面的疏水聚合物复合材料。针对表界面设计与调控、性能协同增强机理等关键科学问题，重点研究分级纳米结构演变、表面修饰、高分子链结构等因素对复合材料表界面结构、界面相互作用、介电/疏水行为的影响规律，阐明分级结构-表界面特性-疏水/介电性能的构效关系，揭示复合材料极化机制、介电-疏水性能协同增强机理，为制备电润湿介电材料提供新方法和理论支持。

本项目旨在解决复合材料表界面设计与调控、性能协同增强机理等关键科学问题，重点开展了以下工作：1、设计合成了花状TiO2及TiO2/C、TiO2纳米线及阵列、纳米线TiO2负载SnO2、Ag纳米线包覆SiO2、聚苯乙烯PS微球表面负载Au等特殊形貌的分级纳米结构颗粒，揭示了分级纳米结构无机颗粒形成机制。2、以分级纳米结构无机颗粒为填料，优选PVDF及共聚物、PDMS、PMMA等聚合物为基体，通过溶液共混法制备复合材料。研究了分级纳米结构类型、表面修饰、聚合物高分子链结构、制备条件等对表界面结构及界面行为的影响，揭示分级纳米结构与聚合物界面相互作用机制，构建出系列具有不同分级界面结构和纳米级粗糙表面的复合介电材料。3、阐明复合聚合物材料表界面结构与疏水特性、热学特性、介电性能的构效关系，揭示了复合材料极化机制、疏水原理以及介电/疏水性能协同增强机理，初步探讨了复合材料储能行为及能量收集特性，通过分级纳米结构尺寸、组分、形貌调节，获得多种兼具高ε和优良疏水特性的介电复合材料。评估了这类分级结构在疏水特性、介电性能、能量存储及能量收集等综合性能提升方面的潜力。本项目研究为高性能无机/有机复合材料设计、制备和应用奠定理论和实验基础。项目研究成果发表SCI收录论文25篇，培养毕业博士生2名、硕士生5名，获授权国家发明专利3项。