School of Mechanical and Aerospace Engineering, World Class University Program on Multiscale Mechanical Design, Seoul National University, Seoul, 151-742, Korea.
Langmuir. 2009 Oct 20;25(20):12024-9. doi: 10.1021/la903236d.
We investigated the capillary rise of a thin polymer solution in a simple soft lithographic technique termed "solvent-assisted molding (SAMo)" by using various mold rising angles and polymer concentrations in a good solvent. For patterning and mold materials, poly(methyl methacrylate) (PMMA, M(w) = 120,000) in toluene and poly(dimethyl siloxane) (PDMS) were mostly used. It was found that the capillary rise takes place in two steps: (i) a low-viscosity polymer solution rapidly rises into the cavity (<10 s) with the aid of solvent wetting and (ii) continuous solvent absorption into the mold and evaporation into air. In addition, five distinct microstructures were observed by testing 24 different experimental combinations, which can be classified into completely molded (I), humped (II), completely molded but non-fully filled (III), partially filled (IV), and partially filled meniscal (V) microstructures.
我们采用一种简单的软光刻技术，即“溶剂辅助成型（SAMo）”，研究了在良溶剂中，不同模具上升角度和聚合物浓度下，稀薄聚合物溶液的毛细上升。在图案化和模具材料方面，通常使用聚甲基丙烯酸甲酯（PMMA，M（w）= 120000）在甲苯和聚二甲基硅氧烷（PDMS）中。研究发现，毛细上升分为两个步骤：（i）在溶剂润湿的辅助下，低粘度聚合物溶液迅速上升到腔体内（<10 秒）；（ii）连续的溶剂吸收到模具中并蒸发到空气中。此外，通过测试 24 种不同的实验组合，观察到了五种不同的微观结构，可以将其分为完全成型（I）、驼峰（II）、完全成型但不完全填充（III）、部分填充（IV）和部分填充新月形（V）微观结构。
