壳聚糖材料多级结构的仿生重构及其机理研究

Properties of materials are determined by their microstructure. Evolution through hundreds of millions of years, the structure of natural materials is perfect, resulting in high performance. Structure of natural biomaterials is destroyed, and then reconstructed during the processing using the sol-gel method. But how to regulate material structure and achieve the required performance, that is a significant problem during making use of natural biological resources, and also is a very important scientific problem. In this research, we will analyze the multiple structure of chitosan, and destroy its intermolecular and intramolecular H-bonding interactions by using novel solvent to dissolve chitosan, avoiding rapid degradation in the acid solution. And then chitosan micro-structure will be regulated by controlling the external conditions, biomimic reconstructing multi-level structure of chitosan, thereby enhancing the structural stability and mechanical properties of chitosan material in the wet environment.

材料的微观结构决定其宏观性能。经过几亿年的进化，天然材料的结构十分完美，性能优异。目前采用溶胶凝胶法制备生物质材料，其结构经历了一个破坏和重构的过程，在重构过程中如何调控材料的结构，使其达到所需的目标性能，这是生物质资源开发利用所面对的共同问题，也是关键科学问题。本研究通过分析天然壳聚糖材料的多层次结构，有效破坏壳聚糖分子内与分子间的氢键作用，寻找一条溶解壳聚糖的新方法，避免壳聚糖在酸中快速降解；然后通过控制外部条件，调控壳聚糖的微结构，实现壳聚糖多层次结构的仿生重构，从而提高壳聚糖材料在湿环境下的结构稳定性和力学性能。

材料的微观结构决定其宏观性能。本项目通过酸、碱溶剂体系分别重构壳聚糖材料，采用聚集诱导发光荧光探针进行荧光成像，实现了壳聚糖碱性溶剂体系凝胶化过程示踪的目的，提出了碱性体系仿生重构凝胶化的机理；壳聚糖酸性溶液的凝胶化过程具有逐层特点，基于这一特点可以制备具有多层-取向结构的壳聚糖水凝胶，还可以制备各种不同形状的壳聚糖水凝胶材料，为制备具有复杂有序结构的壳聚糖干态材料提供了一种有效的方法；由酸、碱两个体系制备的壳聚糖水凝胶力学性能存在显著的差异，解释了两体系水凝胶的差异来源，并讨论了基于两体系凝胶化行为的结构设计原则，为仿生重构兼具强度与复杂结构的壳聚糖水凝胶奠定了基础。