湿敏手性纳米纤维素薄膜的自组装制备及表征

Preparation and Characterization of Humidity-Sensitive Chiral Nematic Films from Nanocrystalline Cellulose via Evaporation-Induced Self-Assembly Method

采用硫酸水解硫酸盐漂白针叶浆制备出纳米纤维素（NCC）,通过NCC胶状溶液中的NCC自组装制得了具有手性结构的纤维素薄膜,对NCC形貌、电位进行了分析,并对NCC溶液和固体薄膜中手性结构以及湿敏性能进行了研究。结果表明,NCC为表面带有少量电荷（-22.07 m V）的纳米尺寸棒状结构（长150-250 nm,宽5-15 nm）,当胶状溶液中NCC的质量分数大于2.83%时,NCC组装形成各向异性的手性向列液晶相结构,偏光显微镜下可观察到明显的指纹织构;干燥成膜后,长程左旋手性结构保留。手性纤维素薄膜具有优良的湿敏性能,表面官能团以O-H为主,200℃以下热稳定性良好。

Humidity-sensitive ehiral nematie cellulose film was prepared via evaporation-induced self-assembly method from nanoerystalline cellulose （NCC） suspension, which was prepared from sulfate bleached softwood kraft pulp via sulfuric acid hydrolysis. The morphology and electrical potential of NCC, the ehiral nematie structure and humidity sensitive properties of NCC film were analyzed. The results indicate that the obtained NCC is rod-like （150 -250 nm in length, 5--15 nm in diameter） with the electrical potential of -22.07 mV. With the evaporation of water of NCC aqueous solution, cellulose film can be formed gradually. Together with anisotropie ehiral nematie liquid crystal phase can be formed spontaneously. A critical NCC concentration of 2.83 % is determined at which fingerprint texture of NCC film can be viewed by an optical microscope. The produced NCC film is abundant with surface O- H functional groups, which exhibits excellent thermal stability under 200℃. Humidity sensitive result reveals that with the change of environmental humidity, the film exhibits different color, which indicates the great potential of this material as humidity sensor.