title: Thermal-Responsive Anisotropic Wetting Microstructures for Manipulation of Fluids in Microfluidics.
abstract: We 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.
authors.affiliation: State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Jilin 130012, P. R. China.
authors.forename: Nianzuo
authors.initials: N
authors.lastname: Yu
authors.affiliation: State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Jilin 130012, P. R. China.
authors.forename: Shuli
authors.initials: S
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics (CIOMP), Chinese Academy of Sciences , Beijing 130033, P. R. China.
authors.forename: Yongshun
authors.initials: Y
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Jilin 130012, P. R. China.
authors.forename: Peihong
authors.initials: P
authors.lastname: Xue
authors.affiliation: State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Jilin 130012, P. R. China.
authors.forename: Peng
authors.initials: P
authors.lastname: Ge
authors.affiliation: State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Jilin 130012, P. R. China.
authors.forename: Jingjie
authors.initials: J
authors.lastname: Nan
authors.affiliation: State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Jilin 130012, P. R. China.
authors.forename: Shunsheng
authors.initials: S
authors.lastname: Ye
authors.affiliation: State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Jilin 130012, P. R. China.
authors.forename: Wendong
authors.initials: W
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Jilin 130012, P. R. China.
authors.forename: Junhu
authors.identifier: 0000-0001-9100-6608
authors.initials: J
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Jilin 130012, P. R. China.
authors.forename: Bai
authors.identifier: 0000-0002-3873-075X
authors.initials: B
authors.lastname: Yang
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D016880:Anisotropy; D044085:Microfluidics / Q000379:methods*; D013499:Surface Properties; D013696:Temperature; D017155:Wettability
chemical_list: D000180:Acrylic Resins; C052970:poly-N-isopropylacrylamide