Langmuir. 2018 Jun 26;34(25):7472-7478. doi: 10.1021/acs.langmuir.8b01381. Epub 2018 Jun 11.
Hierarchical structures are commonly observed in nature and possess unique properties. The fabrication of hierarchical structures with well-controlled sizes in different length scales, however, is still a great challenge. To further understand the morphologies and properties of the hierarchical structures, here we present a novel strategy to prepare hierarchical polymer structures by combining the modified breath figure method and the template method. Poly(methyl methacrylate) (PMMA) honeycomb films with regular micropores are first prepared using the modified breath figure method by dipping PMMA films into mixtures of chloroform and methanol. The polymer chains on the honeycomb films are then annealed and wetted into the nanopores of anodic aluminum oxide templates via capillary forces, resulting in the formation of hierarchical polymer structures. The morphologies of the polymer structures, which can be controlled by the molecular weights of the polymers and the concentrations of the polymer solutions, are characterized by scanning electron microscopy. The surface wettabilities of the polymer structures are also examined by water contact angle measurements, and the hierarchical structures are observed to be more hydrophobic than the flat films and honeycomb films. This work not only provides a feasible approach to fabricate hierarchical polymer structures with controlled sizes but also gives a better understanding of the relationship between surface morphologies and properties.
分层结构在自然界中很常见，具有独特的性质。然而，制造具有不同长度尺度且尺寸得到良好控制的分层结构仍然是一个巨大的挑战。为了进一步了解分层结构的形态和性质，我们在这里提出了一种通过结合改进的呼吸图案法和模板法制备分层聚合物结构的新策略。通过将 PMMA 薄膜浸入氯仿和甲醇的混合物中，使用改进的呼吸图案法首先制备具有规则微孔的 PMMA 蜂窝状薄膜。然后，通过毛细作用力将聚合物链退火并润湿到阳极氧化铝模板的纳米孔中，从而形成分层聚合物结构。通过扫描电子显微镜对聚合物结构的形态进行了表征，其形态可以通过聚合物的分子量和聚合物溶液的浓度来控制。还通过水接触角测量来检查聚合物结构的表面润湿性，结果表明分层结构比平膜和蜂窝状膜更疏水。这项工作不仅为制备具有可控尺寸的分层聚合物结构提供了一种可行的方法，而且还更好地理解了表面形态和性能之间的关系。
