Research Interests

My interests lie on exploring both applied and fundamental research in the areas of surface modification, interfacial phenomena, and polymer thin films.  The following are some projects that are being carried out in our research group.
 

(1) Generating gradient surfaces via contact printing based approach: From screening material behaviors to creating templates for novel molecular architectures is possible using the contact printing based gradient surfaces.  However, in order to realize such applications, the surface properties of the underlying gradient surfaces should be well-defined.  In this project, the experimental parameters and transport processes of “ink” molecules from the stamp to the substrate will be evaluated, and the overall goal is to optimum the experimental conditions to generate well-defined gradient surfaces, based on contact printing, for their designated applications.

 

(2) Droplet movements on wettability gradient surfaces: The contact printing based approach allows the generation of various geometries and sizes of wettability gradient surfaces.  These surfaces can then be utilized to investigate the effects of gradient size (i.e. steepness) on the movement of discrete water droplets.  The mechanisms governing the droplet movement appear to vary as the gradient size scales down, and the determination of the mechanisms for the droplet movement is critical when the gradient surfaces are to be utilized in the microfluidics/nanofluidics technology.

 

(3) Protein adsorption/cell attachment on PEG gradient surfaces: PEG gradient surfaces generated by the contact printing based approach are used to investigate protein adsorption and subsequent cell attachment behaviors.  Such gradient surfaces not only controls cell distribution and alignment, but also allows subsequent spatial re-orientation of attached cells.  In addition, such surfaces are ideal for the study of PEG density effects on its molecular conformation, and how that affects on protein adsorption/cell attachment.

 

(4) Utilizing gradient surfaces for enhanced biosensor, bioMEMS devices: A gradient distribution of sensing component is hypothesized to enhance the sensitivity of sensor device especially when the concentration of the compound to be detected is very low.  A gradient surface will be generated via our contact printing based approach by first putting down an active coupler, and then the sensing component, either enzyme or receptor, will be immobilized onto the coupler via either specific coupling chemistry (e.g. EDC/NHS) or lock-and-key interaction (e.g. biotin/avidin). 

 

(5) Assessing antifouling mechanisms of a non-toxic natural product antifoulant – zosteric acid: The use of non-toxic or less toxic natural product antifoulants (e.g. zosteric acid) represents a promising new approach in antifouling coating technology.  However, for these natural antifoulants to be utilized to their full potential, their mechanistic action against fouling organisms needs to be well understood.  Studies are being carried at the molecular, cellular, and biofilm levels to determine the antifouling mechanism of zosteric acid.

 

(6) Alternative, non-lithography based pattern fabrications: Simpler and cost-effective non-lithography based techniques are attractive alternatives to the photolithography based approaches for creating patterns.  Such techniques provide an easy access for researchers to create desired featured templates or patterns.  We are utilizing spontaneous naturally occurring phenomena, such as decaying of liquid films (i.e. dewetting) on a solid support, “tears of wine” (i.e. Marangoni flow), and patterns generated by peeling (i.e. fracture-induced structuring) to develop some fast, simple and in-expensive alternatives.  The followings are some movie clips showing the real-time processes on generating ordered features.

 

(a)   Creating ordered water droplet arrays via Marangoni-flow: hexagonal arrays, square arrays, receding velocity dependent

(b)  Fracture-induced patterns via simple peeling: from edge, high magnification, slightly tilted

 

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