Periodic Parallel Array of Nanopillars and Nanoholes Resulting from Colloidal Stripes Patterned by Geometrically Confined Evaporative Self-Assembly for Unique Anisotropic Wetting
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- 作者：Xiangmeng Li ; Chunhui Wang ; Jinyou Shao ; Yucheng Ding ; Hongmiao Tian ; Xiangming Li ; Li Wang
- 刊名：ACS Applied Materials & Interfaces
- 出版年：2014
- 出版时间：November 26, 2014
- 年：2014
- 卷：6
- 期：22
- 页码：20300-20308
- 全文大小：469K
- ISSN：1944-8252
文摘
In this paper we present an economical process to create anisotropic microtextures based on periodic parallel stripes of monolayer silica nanoparticles (NPs) patterned by geometrically confined evaporative self-assembly (GCESA). In the GCESA process, a straight meniscus of a colloidal dispersion is initially formed in an opened enclosure, which is composed of two parallel plates bounded by a U-shaped spacer sidewall on three sides with an evaporating outlet on the fourth side. Lateral evaporation of the colloidal dispersion leads to periodic 鈥渟tick鈥搒lip鈥?receding of the meniscus (evaporative front), as triggered by the 鈥渃offee-ring鈥?effect, promoting the assembly of silica NPs into periodic parallel stripes. The morphology of stripes can be well controlled by tailoring process variables such as substrate wettability, NP concentration, temperature, and gap height, etc. Furthermore, arrayed patterns of nanopillars or nanoholes are generated on a silicon wafer using the as-prepared colloidal stripes as an etching mask or template. Such arrayed patterns can reveal unique anisotropic wetting properties, which have a large contact angle hysteresis viewing from both the parallel and perpendicular directions in addition to a large wetting anisotropy.