Porous thin films with hierarchical structures formed by self-assembly of zwitterionic comb copolymers
Porous thin films with hierarchical structures formed by self-assembly of zwitterionic comb copolymers
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DOI：
10.1016/j.apsadv.2022.100361
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发表时间：
2023-02
影响因子：
6.2
通讯作者：
Papatya Kaner;Ilin Sadeghi;A. Asatekin
中科院分区：
文献类型：
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作者：
Papatya Kaner;Ilin Sadeghi;A. Asatekin
两性离子表现出高的偶极矩和强的分子内和分子间相互作用。因此，具有两性离子重复单元的两亲性共聚物很容易自组装。在这里，我们探讨了广泛的自组装形态形成的两性离子梳形共聚物（ZCC），包括一个疏水性的骨干和两性离子侧链。我们研究了聚合物结构、体系结构和成膜方法对自组装形貌的影响。我们合成了具有不同两性离子侧链密度和长度的ZCC，并使用不同的方法将每个ZCC作为薄膜施加在玻璃基底上。我们比较了这些薄膜的形态与ZCCs薄膜涂覆在多孔基板上的非溶剂诱导相分离，创建机械支撑的薄膜（MSTFs），并比较它们与非多孔基板上的薄膜。多孔载体导致膜形态的明显变化，产生分层特征，包括沿着具有较大纳米孔（约85 nm）的约17 nm球形胶束。该特征尺寸可以使用两性离子均聚物添加剂来调节。MSTF在暴露于已知刺激两性离子侧链扩张的盐水溶液后表现出水渗透性和形态的显著变化。这些结果证明了该梳形共聚物家族可获得的宽范围的形态，并证明了多孔载体对成膜过程的显著影响。
Zwitterions exhibit high dipole moments and strong intra- and inter-molecular interactions. As a result, amphiphilic copolymers with zwitterionic repeat units easily self-assemble. Here, we explore the wide range of self-assembled morphologies formed by zwitterionic comb-shaped copolymers (ZCCs) comprising a hydrophobic backbone and zwitterionic side-chains. We study the effect of polymer structure, architecture, and film preparation method on self-assembled morphology. We synthesized ZCCs with varying zwitterionic side chain density and length, and applied each ZCC as a thin film on glass substrates using different methods. We compared the morphology of these films with ZCCs films coated on a porous substrate by non-solvent induced phase separation, creating mechanically supported thin films (MSTFs) and comparing them with films on non-porous substrates. The porous support led to distinct changes in film morphology, creating hierarchical features including ∼17 nm spherical micelles along with larger nanopores (∼85 nm). This feature size could be tuned using a zwitterionic homopolymer additive. MSTFs exhibited significant changes in water permeance and morphology upon exposure to saline solutions, known to stimulate expansion of the zwitterionic side-chains. These results demonstrate the wide range of morphologies accessible by this comb copolymer family and document the significant effect of a porous support on the film formation process.