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Download fileThermal-Responsive Anisotropic Wetting Microstructures for Manipulation of Fluids in Microfluidics
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posted on 21.12.2016, 00:00 authored by Nianzuo Yu, Shuli Wang, Yongshun Liu, Peihong Xue, Peng Ge, Jingjie Nan, Shunsheng Ye, Wendong Liu, Junhu Zhang, Bai YangWe show morphology-patterned
stripes modified by thermal-responsive
polymer for smartly guiding flow motion of fluid in chips. With a
two-step modification process, we fabricated PNIPAAm-modified Si stripes
on silicon slides, which were employed as substrates for fluid manipulation
in microchannels. When the system temperature switches between above
and below the lower critical solution temperature (LCST) of PNIPAAm,
the wettability of the substrates also switches between strong anisotropy
and weak anisotropy, which resulted in anisotropic (even unidirectional)
flow and isotropic flow behavior of liquid in microchannels. The thermal-responsive
flow motion of fluid in the chip is influenced by the applied pressure,
the thickness of PNIPAAm, and dimension of the microchannels. Moreover,
we measured the feasible applied pressure scopes under different structure
factors. Because of the excellent reversibility and quick switching
speed, the chip could be used as a thermal-responsive microvalve.
Through tuning the system temperature and adding the assistant gas,
we realized successive “valve” function. We believe
that the practical and simple chip could be widely utilized in medical
detection, immunodetection, protein analysis, and cell cultures.
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flow behaviorchipsystem temperature switchesThermal-Responsive Anisotropic Wetting Microstructuresassistant gasthermal-responsive flow motionstructure factorsthermal-responsive microvalveflow motionmicrochannelshow morphology-patterned stripesthermal-responsive polymerprotein analysismodification processsolution temperaturefluid manipulationcell culturesLCSTsubstratePNIPAAm-modified Si stripesanisotropysilicon slidespressure scopessystem temperature