Switching water droplet adhesion using responsive polymer brushes.
Two stimuli-responsive polymers, poly(N-isopropylacrylamide) (PNIPAM) and poly(dimethylamino)ethyl methacrylate (PDMAEMA), were grafted from initiator-modified anodized alumina substrates with irregular micro/nanoscale surface topography. The resulting polymer-coated surfaces exhibited highly unusual wettability properties, as spherical water/acid/alkali/salt droplets could be reversibly switched between pinned states and rolling states due to the changes of temperature, pH, and electrolytes. The key to this effect is the combination of a mixed monolayer which provides initiator points for brush growth as well as a permanently hydrophobic substrate and a surface roughness.
Liu
Xinjie
X
State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, PR China.
Ye
Qian
Q
Yu
Bo
B
Liang
Yongmin
Y
Liu
Weimin
W
Zhou
Feng
F
D000180:Acrylic Resins / Q000737:chemistry*; D054879:Halogenation; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D008689:Methacrylates / Q000737:chemistry*; D009757:Nylons / Q000737:chemistry*; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
D000180:Acrylic Resins; D008689:Methacrylates; D009757:Nylons; C407037:poly(2-(dimethylamino)ethyl methacrylate); D014867:Water; C052970:poly-N-isopropylacrylamide