1. Droplet-driven transports on superhydrophobic-patterned surface microfluidics
- Author
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Siyuan Xing, Ryan S. Harake, and Tingrui Pan
- Subjects
Surface (mathematics) ,Polydimethylsiloxane ,Surface Properties ,Chemistry ,Microfluidics ,Biomedical Engineering ,Bioengineering ,Nanotechnology ,General Chemistry ,Models, Theoretical ,Biochemistry ,Surface tension ,Droplet merging ,chemistry.chemical_compound ,Dimethylpolysiloxanes ,Wetting ,Transport phenomena ,Hydrophobic and Hydrophilic Interactions ,Laser micromachining - Abstract
Droplet-based transport phenomena driven by surface tension have been explored as an automated pumping source for a number of chemical and biological applications. In this paper, we present a comprehensive theoretical and experimental investigation of unconventional droplet-based motions on a superhydrophobic-patterned surface microfluidic (S(2)M) platform. The S(2)M surfaces are monolithically fabricated using a facile two-step laser micromachining technique on regular polydimethylsiloxane (PDMS) chemistry. Unlike the traditional droplet-driven pumps built on an enclosed microfluidic network, the S(2)M network pins the liquid-solid interface of droplets to the lithographically defined wetting boundary and establishes a direct linkage between the volumetric and hydraulic measures. Moreover, diverse modes of droplet motions are theoretically determined and experimentally characterized in a bi-droplet configuration, among which several unconventional droplet-driven transport phenomena are first demonstrated. These include big-to-small droplet merging, droplet balancing, as well as bidirectional transporting, in addition to the classic small-to-big droplet transition. Furthermore, multi-stage programmable bidirectional pumping has been implemented on the S(2)M platform, according to the newly established droplet manipulation principle, to illustrate its potential use for automated biomicrofluidic and point-of-care diagnostic applications.
- Published
- 2011