MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, China.
J Phys Chem B. 2012 Jan 12;116(1):40-7. doi: 10.1021/jp208115u. Epub 2011 Dec 27.
The control of the pore size of honeycomb-patterned films has been more or less involved in most work on the topic of breath figures. Modulation of the pore shape was largely ignored, although it is important to applications in replica molding, filtration, particle assembly, and cell culture. This article reports a tunable pore shape for patterned films prepared from commercially available polystyrene (PS). We investigated the effects of solvents including tetrahydrofuran (THF) and chloroform (CF) and hydrophilic additives including poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA), poly(ethylene glycol) (PEG), and poly(N-vinyl pyrrolidone) (PVP). Water droplets on/in the polymer solutions were observed and analyzed for simulating the formation and stabilization of breath figures. Interfacial tensions of the studied systems were measured and considered as a main factor to modulate the pore shape. Results indicate that the pores gradually change from near-spherical to ellipsoidal with the increase of additive content when using CF as the solvent; however, only ellipsoidal pores are formed from the THF solution. It is demonstrated that the aggregation of the additives at the water/polymer solution interface is more efficient in the THF solution than that in the CF solution. This aggregation decreases the interfacial tension, stabilizes the condensed water droplets, and shapes the pores of the films. The results may facilitate our understanding of the dynamic breath figure process and provide a new pathway to prepare patterned films with different pore structures.
在涉及到呼吸图形主题的大多数工作中，或多或少都会涉及到对蜂窝状图案膜的孔径控制。尽管在复制成型、过滤、颗粒组装和细胞培养等应用中，孔形状的调制非常重要，但它在很大程度上被忽视了。本文报道了一种来自市售聚苯乙烯（PS）的图案化薄膜的可调孔径。我们研究了包括四氢呋喃（THF）和氯仿（CF）在内的溶剂以及包括聚（N，N-二甲基氨基乙基甲基丙烯酸酯）（PDMAEMA）、聚乙二醇（PEG）和聚（N-乙烯基吡咯烷酮）（PVP）在内的亲水性添加剂的影响。观察了聚合物溶液中的水滴并进行了分析，以模拟呼吸图形的形成和稳定。测量了所研究系统的界面张力，并将其视为调节孔径的主要因素。结果表明，当使用 CF 作为溶剂时，随着添加剂含量的增加，孔逐渐从近球形变为椭圆形；然而，仅从 THF 溶液中形成椭圆形孔。结果表明，添加剂在水/聚合物溶液界面处的聚集在 THF 溶液中比在 CF 溶液中更有效。这种聚集降低了界面张力，稳定了浓缩的水滴，并形成了薄膜的孔。结果可能有助于我们理解动态呼吸图形过程，并为制备具有不同孔结构的图案化薄膜提供新途径。
