Centre de Recherches sur les Macromolécules Végétales (CERMAV-CNRS), BP 53, 38041 Grenoble Cedex 9, France.
Biomacromolecules. 2010 Dec 13;11(12):3652-9. doi: 10.1021/bm101106c. Epub 2010 Nov 8.
The grafting of thermosensitive amine-terminated statistical polymers onto the surface of cellulose nanocrystals (CNCs) was achieved by a peptidic coupling reaction, leading to unusual properties like colloidal stability at high ionic strength, surface activity, and thermoreversible aggregation. We have used a large variety of experimental techniques to investigate the properties of the polymer-decorated CNCs at different length-scales and as a function of the different reaction parameters. A high grafting density could be obtained when the reaction was performed in DMF rather than water. Infrared and solid-state NMR spectroscopy data unambiguously demonstrated the covalent character of the bonding between the CNCs and the macromolecules, whereas TEM images showed a preserved individualized character of the modified objects. Dynamic light scattering and zeta potential measurements were also consistent with individual nanocrystals decorated by a shell of polymer chains. Surface tension measurements revealed that CNCs became surface-active after the grafting of thermosensitive amines. Decorated CNCs were also stable against high electrolyte concentrations. A thermoreversible aggregation was also observed, which paves the way for the design of stimuli-responsive biobased nanocomposite materials.
通过肽键偶联反应，将温敏性胺封端的统计聚合物接枝到纤维素纳米晶体（CNC）表面，得到了具有独特性能的纳米复合材料，如在高离子强度下的胶体稳定性、表面活性和热可逆聚集。我们使用了多种实验技术，在不同的长度尺度上研究了聚合物修饰的 CNC 的性质，并研究了不同反应参数的影响。当反应在 DMF 中而不是水中进行时，可以获得较高的接枝密度。红外和固态 NMR 光谱数据明确表明了 CNC 与大分子之间键合的共价性质，而 TEM 图像则显示了修饰物体的个体特征得以保留。动态光散射和zeta 电位测量也与聚合物链壳修饰的单个纳米晶体一致。表面张力测量表明，接枝温敏性胺后，CNC 具有表面活性。经过修饰的 CNC 也能抵抗高电解质浓度。还观察到了热可逆聚集，这为设计刺激响应型生物基纳米复合材料铺平了道路。
