In this work, a series of oil soluble diblock copolymers poly(methyl methacrylate)-b-poly[2-(dimethylamino)ethyl methacrylate] (PMMAm-b-PDEAEMAn; where m is fixed at 49 and n is varied from 3 to 12) are synthesized using a reversible addition-fragmentation chain transfer RAFT method. The copolymers exhibit pH-dependant interfacial activities and behave as macromolecular surfactants under strong acidic conditions. The coassembly behavior and kinetics of cellulose nanocrystals (CNCs) and the copolymer at the water/toluene interface is probed by tracking the dynamic interfacial tension using pendant drop tensiometry. At low pH such as 2 and 3, the film that CNCs coassemble with the copolymer at the oil/water interface can stabilize the pendant drop from dripping down. At a higher pH value, CNCs enhance the interfacial activity of the copolymer through interfacial tension measured and emulsions test. When investigating the coassembly kinetics, it is found that the interfacial protonation reaction of the copolymer and absorbing at the oil/water interface is the rate-determining step and electrostatic binding with CNCs is a much faster process. Besides, the interfacial activity of PMMAm-b-PDEAEMAn is enhanced as n increases and the interfacial coassembly with CNCs is accelerated. A nanoparticle film can be formed because of the coassembly behavior of CNCs and diblock copolymers at the oil/water interface and can stabilize the liquid/liquid interface and endow the interface elastic property. Based on this property, liquid tubule can be generated through injecting CNC aqueous dispersion to copolymer toluene solution. This formation of liquid tubule opens a new platform for the additive manufacturing technique of three-dimensional printing of liquid constructs.

中文翻译：

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纤维素纳米晶体和 pH 响应双嵌段共聚物 PMMA-b-PDEAEMA 在油/水界面上的共组装行为和动力学，并应用于液体小管形成

在这项工作中，一系列油溶性二嵌段共聚物聚（甲基丙烯酸甲酯）-b-聚[2-（二甲氨基）甲基丙烯酸乙酯]（PMMAm-b-PDEAEMAn；其中 m 固定为 49，n 为 3 到 12 ) 是使用可逆加成-断裂链转移 RAFT 方法合成的。该共聚物表现出依赖于 pH 值的界面活性，在强酸性条件下表现为大分子表面活性剂。通过使用悬滴张力测定法跟踪动态界面张力来探测纤维素纳米晶体 (CNC) 和共聚物在水/甲苯界面处的共组装行为和动力学。在低 pH 值（例如 2 和 3）下，CNC 与共聚物在油/水界面处共同组装的薄膜可以稳定悬滴，防止滴落。在较高的 pH 值下，CNCs 通过界面张力测量和乳液测试增强了共聚物的界面活性。在研究共组装动力学时，发现共聚物的界面质子化反应和在油/水界面处的吸收是决定速率的步骤，而与 CNC 的静电结合是一个更快的过程。此外，PMMAm-b-PDEAEMAn 的界面活性随着 n 的增加而增强，并加速了与 CNC 的界面组装。由于CNCs和二嵌段共聚物在油/水界面的共组装行为，可以形成纳米颗粒膜，并可以稳定液/液界面并赋予界面弹性。基于这一特性，可以通过将 CNC 水分散体注入共聚物甲苯溶液中来生成液体小管。