仿生超疏水奈微米結構表面製造與分析及其於可逆式微液珠電致操控之應用

Preparation and Analysis of Biomimic Superhydrophobic Surface and its Application on Reversible Electro Microdroplet Manipulation

陳明宏(Ming-Hung Chen)

指導教授 ： 曾繁根 ； 錢景常

國立清華大學/工學院/奈米工程與微系統研究所/博士(2009年)

摘要

本論文研究之目的在於利用仿生的觀點來進行結構引發超疏水表面之製作、分析及其電製微流體操控之應用。本研究成功發展一套電漿蝕刻引發自我成型之高分子奈米絲成形技術，免除傳統製作奈米結構時的奈米微影需求，以不須歷經在無機奈米絲製程下的高溫條件，具有極佳的奈微機電製程整合彈性。藉由荷葉仿生之概念成功並配合微米結構之製程，製作出具有奈微米尺度複合結構仿生超疏水表面，其極佳之超疏水特性(接觸角 > 155度)與極低的遲滯角(遲滯角 < 10度)，堪與荷葉表面相仿。就應用面而言，液珠在此超疏水表面之動態過程的現象闡述與分析更形重要，然而受限於結構製備之限制尚無充分的研究，有鑑於此，研究中藉由液珠衝擊試驗來探討液珠與多重尺度結構表面之間接觸角時變關係與形貌變化，並分析其複合尺度結構所存在之多重介穩態與階層結構間潤濕過程所存在之能障。為改善自我成型奈米結構之材料機械特性與提升材料表面之本質接觸角，以提升超疏水表面於後續應用上之穩定度，繼而探討利用Parylene-C高分子氣相沉積以強化結構並建置一套鐵氟龍疏水材料霧化噴塗系統，在維持表面奈米結構之形貌為前提下，分析證實其表面疏水特性有顯著之改善，其接觸角可進一步達到165度而遲滯可大幅降低至3度以下。
在應用方面，吾人嘗試將此一仿生超疏水表面整合應用至電潤濕微流體控制系統中以探討其電致動之過程，結果顯示液珠可以在配合有Parylene-C結構強化與鐵氟龍疏水修飾之奈米結構表面成功進行可逆式電潤濕之原位致動與橫向移動，其最大之接觸角改變量可達~50度(電壓條件：150 Vac)。

關鍵字

超疏水 ； 仿生 ； 電潤濕 ； 多重尺度結構 ； 奈米絲

並列摘要

The purpose of this dissertation is to develop and analyze a biomimic texture-induced superhydrophobic (SHP) surface as well as applied to the manipulation of electro-induced microfluidic systems. In this study, a novel fabrication of self-forming high-aspect-ratio polymer nanopillars under reactive ion etching (RIE) process was proposed in which the fabrication process need neither nano-lithography definition nor catalyst pre-forming during inorganic growing and showed a highly integration flexibility of other N/MEMS fabrication processes. Based on lotus leaf biomimic, a SHP surface with multi-length scale was successfully constructed and the contact angle (CA) can be larger than 155o and the contact angle hysteresis (CAH) can be less than 10o which was similar to the properties of real lotus leaf. In the application aspect, it is more important of the phenomena description and theoretical study of the dynamic process on such a hierarchical SHP surface. Due to the limitation of the preparation of hierarchical SHP surface, however, the study of droplet dynamic impinging to the surface was still insufficient. As a result, the free fall droplet impinging test onto SHP surface was observed and analyzed in droplet deformation and time-varied CA so as to categorized the three wetting schemes: non-wetting, micro-wetting, and nano-wetting and the textured-induced energy barriers were estimated. In order to improve the SHP stability, Parylene-C coating and Teflon spray coating were utilized to increase the rigidity and intrinsic CA of polymer nanopillars. The result shows a better SHP surface with higher CA (~165o) and lower CAH (<3o). For further application, the biomimic SHP surface was integrated with electro-induced microfluidic manipulation system and demonstrated a reversible actuation of in-situ droplet deformation and lateral moving on nanopillars SHP surface. The contact angle decrease can up to 50o under voltage applied of 150 Vac.

並列關鍵字

Superhydrophobic ； Biomimic ； Electrowetting ； Multi-length scale structure ； Nanopillars

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