Surface Modification of Organic and Inorganic Materials
Methods for modifying the surfaces of organic and inorganic materials are developed to enhance their performance in such areas as adhesion, friction, wetting, and biocompatibility. The technologies of self-assembled organic monolayers and grafted polymers are used to modify the surfaces of a whole range of polymers, metals, and ceramics. Various analytical techniques are used to characterize the properties of modified surfaces.
Adhesion and Friction of Soft Polymers
Methods are developed for estimating the interaction energies and friction involving elastomeric polymers. We try to understand how the adhesion and friction depend on surface energetics, geometric and mechanical properties as well as the various energy dissipative processes at the surface and the bulk of the polymer. We also try to understand how patterning a surface with discontinuities arrests a crack and thus give rise to higher fracture toughness. The results of these studies have potential applications in (1) low friction surfaces (2) easy release surfaces and (3) biomimetic adhesives, to name a few. This research is funded by Office of Naval Research and Pennsylvania Infrastructure for Technology Alliance.
In this study we try to understand the energetics and dynamics of interactions of liquid drops with homogeneous as well as gradient surfaces. A key point of our research is to understand the origin of hysteresis at liquid/solid interfaces. We are also developing various methods to induce motion of liquid drops on surfaces using vibration. This research has potential application in the development of new microflidic devices. This research is funded by the Pennsylvania Infrastructure for Technology Alliance.
In this collaborative study with Boeing Airplane Corporation, we try to develop strong adhesive joints between metals and polymers using a sol-gel technology. We use various fracture mechanics and surface analytical techniques to understand the stability of adhesive joints under aggressive environmental conditions.
Adhesion to Skin and Mucous Membrane
This is a relatively new project funded by National Starch and Chemical Co, in which we are trying to understand the various factors behind the adhesion of medical adhesives to skin and mucous membrane.
Instabilities in Thin Elastomeric Films
We have been working for several years to understand the nature of instability that occurs in thin elastomeric films. It turns out that the instability is purely elastic and arises due to minimization of shear deformation energy in the film. This phenomenon manifest in terms of the fingering instability, cavitation and various other forms of pattern forming systems that is both aesthetically pleasing and potentially useful in various practical situations.