[Soft Matter] Smart Design of Wettability-Patterned Gradient on Substrate-Independent Coated Surface
Highly adherent wettability patterns on substrate-independent superhydrophobic surfaces of trimethoxyoctadecylsilane modified titanium dioxide (TiO2)-based coatings were prepared by using commercial photolithography. Three custom unidirectional channels with gradient wettability patterns were obtained by spatially selective wettability conversion from superhydrophobic to superhydrophilic when the coatings were exposed to ultraviolet light (~365 nm). The movement behavior of droplets on these unidirectional channels was studied and the displacement of droplet movement was effectively controlled. Integrating the idea of gradient wettability pattern into the plane microfluidic devices (microreactors), a self-driven fluid transport was achieved to realize the droplet metering, merging or reaction and rapid transport. This self-driven fluid transport with gradient wettability patterns has a great potential as a new category of pump-free microfluidic systems used in various conditions.
Huaping Wu, Kai Zhu, Binbin Cao, Zheng Zhang, Bingbing Wu, Lihua Liang, Guozhong Chai and Aiping Liu
Soft Matter, 2017, Accepted Manuscript
DOI: 10.1039/C6SM02864K Received 23 Dec 2016, Accepted 23 Mar 2017 First published online 24 Mar 2017