Department of Chemical Engineering, University of Florida, Gainesville, FL 32611, USA.
Department of Chemical Engineering, University of Florida, Gainesville, FL 32611, USA.
J Colloid Interface Sci. 2017 Feb 1;487:484-492. doi: 10.1016/j.jcis.2016.10.081. Epub 2016 Oct 28.
Here we report an unconventional colloidal lithography approach for fabricating a variety of periodic polymer nanostructures with tunable geometries and hydrophobic properties. Wafer-sized, double-layer, non-close-packed silica colloidal crystal embedded in a polymer matrix is first assembled by a scalable spin-coating technology. The unusual non-close-packed crystal structure combined with a thin polymer film separating the top and the bottom colloidal layers render great versatility in templating periodic nanostructures, including arrays of nanovoids, nanorings, and hierarchical nanovoids. These different geometries result in varied fractions of entrapped air in between the templated nanostructures, which in turn lead to different apparent water contact angles. Superhydrophobic surfaces with >150° water contact angles and <5° contact angle hysteresis are achieved on fluorosilane-modified polymer hierarchical nanovoid arrays with large fractions of entrapped air. The experimental contact angle measurements are complemented with theoretical predictions using the Cassie's model to gain insights into the fundamental microstructure-dewetting property relationships. The experimental and theoretical contact angles follow the same trends as determined by the unique hierarchical structures of the templated periodic arrays.
我们在此报告一种非传统的胶体光刻方法，用于制造具有可调几何形状和疏水性的各种周期性聚合物纳米结构。首先通过可扩展的旋涂技术组装晶圆尺寸的双层、非密堆积二氧化硅胶体晶体嵌入聚合物基质中。不常见的非密堆积晶体结构结合薄聚合物膜将顶层和底层胶体层隔开，为周期性纳米结构的模板提供了很大的通用性，包括纳米空隙、纳米环和分级纳米空隙阵列。这些不同的几何形状导致在模板化纳米结构之间存在不同比例的被困空气，这反过来又导致不同的表观水接触角。在氟化硅烷改性聚合物分级纳米空隙阵列上实现了>150°水接触角和<5°接触角滞后的超疏水表面，其中被困空气的比例较大。实验接触角测量结果通过使用 Cassie 模型进行理论预测得到补充，以深入了解基本的微观结构-去湿性质关系。实验和理论接触角遵循相同的趋势，由模板周期性阵列的独特分级结构决定。
