Brief introduction of our researches
I. Swelling behavior of polyelectrolyte multilayers.
Polyelectrolyte multilayers (PEMs), assembled from weak polyelectrolytes, have often been proposed for use as smart or responsive materials. However, such response to chemical stimuli has been limited to aqueous environments with variations in ionic strength or pH. In this work, a large in magnitude and reversible transition in both the swelling/shrinking and the viscoelastic behavior of branched polyethylenimine/poly(acrylic acid) multilayers was realized in response to exposure with various polar organic solvents (e.g., ethanol, dimethyl sulfoxide, and tetrahydrofuran).
II. Mechanical transition of polymeric films
The entropy-driven layer-by-layer (LbL) assembly of thin branched polyethylenimine (BPEI)/poly(acrylic acid) (PAA) polyelectrolytes films was prepared for the study of mechanical transition. The peeling test was implemented to measure adhesive forces of (BPEI/PAA) multilayer films. Wet adhesive behavior of BPEI/PAA multilayers under different pH, various metal ions as well as metal concentration was studied and zeta potential of these films was also monitored to correlate adhesion behavior and films under various conditions.
III. Thermodynamic and kinetic properties of polyelectrolyte complexes
Polyelectrolyte multilayers (PEMs) are a versatile type of thin film fabricated via the layer-by-layer (LBL) assembly based on directed complexation of oppositely charged polyelectrolytes. This can also be accomplished by harnessing materials with other types of associations like hydrogen bonds and π-π interaction. Polyelectrolyte complexes (PECs) have attracted considerable interest in a range of applications. This includes PEMs, which are thermodynamically very similar to complexes, which present a wide range of applications, such as sensors, separation membrances, coatings, and barrier materials. Therefore the investigation of thermodynamics and kinetics of complexation of polyelectrolyte becomes important, and provides a convenient way to study PEMs.
IV. Slippery Liquid-infused polyelectrolyte multilayers
Slippery Liquid-infused polyelectrolyte multilayers have been shown to have properties including low contact angle hysteresis and low sliding angles. Recently, we have found a superior anti-icing property of this polyelectrolyte multilayers. We are also working on this coating associated with living cells in order to create non-fouling/anti-bacteria surfaces.