Self-Assembling Behavior of Cellulose Nanoparticles during Freeze-Drying: Effect of Suspension Concentration, Particle Size, Crystal Structure, and Surface Charge
Self-Assembling Behavior of Cellulose Nanoparticles during Freeze-Drying: Effect of Suspension Concentration, Particle Size, Crystal Structure, and Surface Charge
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DOI：
10.1021/bm4001734
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发表时间：
2013-05-01
影响因子：
6.2
通讯作者：
Wu, Qinglin
中科院分区：
文献类型：
--
作者：
Han, Jingquan;Zhou, Chengjun;Wu, Qinglin
通过碱预处理和酸水解从漂白木纤维中分离出纤维素纳米晶体和具有I和II晶体同晶型的纤维素纳米纤维（命名为CNC I、CNC II、CNF I和CNF II）。研究了浓度、粒径、表面电荷和晶体结构对纤维素颗粒在水悬浮液中冻干诱导自组装的影响。在0.5 - 1.0wt%的浓度范围内，纤维素颗粒自组织成由宽度为0.5 - 3 μ m的对齐的膜层组成的层状结构泡沫。在0.05wt%时，CNC I、CNF I、CNC II和CNF II分别自组装成平均直径为0.57、1.02、1.50和1.00 μ m的取向超细纤维。纤维素表面羟基越多，硫酸根越少（静电排斥力越弱），自组装纤维的尺寸越大。可能的形成机制推断从冰的生长和纤维素纳米粒子在液晶悬浮液之间的相互作用。
Cellulose nanocrystals and cellulose nanofibers with I and II crystalline allomorphs (designated as CNC I, CNC II, CNF I, and CNF II) were isolated from bleached wood fibers by alkaline pretreatment and acid hydrolysis. The effects of concentration, particle size, surface charge, and crystal structure on the lyophilization-induced self-assembly of cellulose particles in aqueous suspensions were studied. Within the concentration range of 0.5 to 1.0 wt %, cellulose particles self-organized into lamellar structured foam composed of aligned membrane layers with widths between 0.5 and 3 mu m. At 0.05 wt %, CNC I, CNF I, CNC II, and CNF II self-assembled into oriented ultrafine fibers with mean diameters of 0.57, 1.02, 1.50, and 1.00 mu m, respectively. The size of self-assembled fibers became larger when more hydroxyl groups and fewer sulfates (weaker electrostatic repulsion) were on cellulose surfaces. Possible formation mechanism was inferred from ice growth and interaction between cellulose nanoparticles in liquid-crystalline suspensions.