非聚醚类两亲性高分子模板剂导向合成具有可控结构的大孔径介孔碳-金属氧化物复合材料

In this proposal, we will design home-made non-Pluronic amphiphillic block copolymers (e.g. PEO-b-PS) with high-molecular weights and use them to direct the assembly of pre-synthesized hydrophobic metal oxide nanoparticles (typically iron oxides and tungsten oxides) via spin-coating casting their solutions on silicon substrate, followed with solvent annealing. It will generate metal oxide/ PEO-b-PS nanocomposites with ordered mesostructures. The ordered mesostructures can be fixed via in-sequence exposure of the composites in the vapor of resorcinol (or phloroglucinol) and formaldehyde due to the formation of thermoset phenolic resin. A further pyrolysis treatment at optimum temperatures and ramping rate to selectively remove the PEO-b-PS template and then carbonize the phenolic resin, ordered mesoporous carbon with pores filled by metal oxide nanoparticles can be obtained. A systematic investigation will be carried out to elucidate the mechanism about how the template molecules guide the assembly of hydrophobic metal oxide nanoparticles, and to obtain optimum conditions for formation of composites with ordered mesostructures, including the template/metal oxide weight ratio, solvent nature, particle sizes, the molecular weights of copolymers, active vapors' concentrations, polymerization temperature, pyrolysis treatment programs (ramping rate, pyrolysis temperature), etc. By using the obtained mesoporous carbon-metal oxide composites as the electrode materials, extensive electrochemical measurements will be carried out, including cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and cycling stability tests, to study the specific capacitance, rate capability, energy density and cyclability of the obtained materials. The results of this study are expected to elucidate the relationship and the nanostructure, composition and textural features of the nanocomposites and help to guide advanced mesoporous composite materials with multicomponents and integrated properties for applications in energy storage.

本项目结合高分子嵌段共聚物微相分离、胶体组装以及介孔材料软模板合成法，设计一系列超高分子量的两亲性嵌段共聚物模板剂（如PEO-b-PS），通过溶剂退火的策略，使其与疏水金属氧化物颗粒协同组装形成介观有序复合体，然后通过原位酚醛聚合“锁定”介观结构，最后在惰性气氛中煅烧处理复合物，使模板剂分解，酚醛树脂碳化，得到介孔碳-金属氧化物复合材料。研究组装条件（如溶剂类型、模板剂组成、氧化物颗粒的尺寸等）对复合介观结构形成的影响；研究复合物中软模板与间苯二酚（或均苯三酚）蒸气的作用规律及后续甲醛气氛下酚醛聚合速率等因素对固定介观结构效果的影响；研究煅烧条件等因素对于介孔碳-金属氧化物的结构及性能的影响。发展具有较大孔径（5-30 nm）、可控结构和组成以及优异电化学性能的介孔碳-金属氧化物复合材料，论证其结构、组成与电化学储能性能的关系，为发展高性能多功能、多组分集成的介孔复合材料奠定一定的基础。

非聚醚类两亲性嵌段共聚物作为一类极具应用价值和推广价值的表面活性剂已经广泛应用于多种复杂结构、组分及功能调控的介孔材料合成体系。通过设计具有不同分子嵌段、分子量的嵌段共聚物，可以实现介孔碳-金属氧化物复合材料的孔径调控与结构优化。嵌段分子能够在高温下转化为无定形sp2杂化碳，极大地提升了介孔材料孔道的稳定性和有序度。本项目紧密围绕非聚醚类两亲性高分子模板剂的设计合成展开研究，系统开发了一系列具有高比表面积、高化学活性的介孔金属氧化物材料及其复合材料的合成的新策略和方法。结合凝胶-溶胶界面组装化学及sp2-杂化碳支撑晶化策略，精准设计合成了一系列具有催化、传感反应活性的功能纳米材料，深入揭示和阐明了界面组装作用机制和表/界面催化作用机理。相关研究成果发表于Nat. Mater.、J. Am. Chem. Soc.、Adv. Mater.等材料化学顶级期刊，共计40篇SCI论文，同时申请了4件中国发明专利，授权2件，该项目研究成果推动了介孔功能材料及相关学科的发展，为新型介孔材料的开发奠定了理论基础。