Cellulose nanocrystals (CNCs) were converted into a CO₂-responsive composite nanomaterial by grafting poly(dimethylaminoethyl methacrylate) (PDMAEMA), poly(diethylaminoethyl methacrylate) (PDEAEMA), and poly(diisopropylaminoethyl methacrylate) (PDPAEMA) onto its surface using both grafting-to and grafting-from approaches. The zeta potential (ζ) of the graft-modified CNC could be reversibly switched by protonation/deprotonation of the tertiary amine groups simply by sparging with CO₂ and N₂, respectively. Depending on the grafting density and the molecular weight of the polymer grafts, CNC can form stable aqueous dispersions at either mildly acidic pH (under CO₂) or mildly basic (under N₂) conditions. Moreover, it was also determined that the CNC hydrophobicity, assessed using phase-shuttling experiments at different pH values, was also dependent on both the grafting density and molecular weight of the polymer grafts, thereby making it possible to easily tune CNC dispersibility and/or hydrophobicity.

中文翻译：

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通过CO ₂响应单体调节疏水性的RAFT聚合对纤维素纳米晶体进行表面修饰

纤维素纳米晶体（CNCs）通过使用两种接枝方法将聚甲基丙烯酸二甲基氨基乙基酯（PDMAEMA），聚甲基丙烯酸二乙基氨基乙基酯（PDEAEMA）和聚甲基丙烯酸二异丙基氨基乙基酯（PDPAEMA）接枝到其表面，从而转化为对CO ₂响应的复合纳米材料。 -和嫁接-方法。只需分别向CO ₂和N ₂喷射，即可通过叔胺基的质子化/去质子化，可逆地切换接枝改性CNC的zeta电位（ζ）。根据接枝密度和聚合物接枝物的分子量，CNC可以在弱酸性pH（在CO _2下）或弱碱性（在N ₂下）形成稳定的水分散体。） 条件。此外，还确定了使用相穿移实验在不同pH值下评估的CNC疏水性还取决于聚合物接枝的接枝密度和分子量，从而可以轻松调节CNC分散性和/或疏水性。