Adhesion study at the interface of PDMS-elastomer and borosilicate glass-slide: Effect of modulus and thickness of elastomer

Abstract

Adhesion control at the interface of two surfaces is crucial in many applications. Examples are the design of micro and nanodevices such as microfluidic devices, biochips, and electronic sensors. Adhesion at the interface of two materials can be controlled by various methods such as chemical treatment on the surface of the materials, modification of the surface texture of materials, and change of the mechanical properties of materials. The main idea of this study is to control the adhesion by changing the mechanical properties (modulus) of polydimethylsiloxane (PDMS) elastomer. We vary the modulus of PDMS elastomer by changing the silicone elastomer base’s mixing ratio (w/w) and its curing agent (Sylgard^TM 184, Dow Corning). Our study also includes the effect of the thickness of the PDMS elastomer sheet on its adhesion behavior. Adhesion measurements at the interface of the borosilicate glass slide and different PDMS elastomer specimens were performed using a wedge test. This method inserts a glass coverslip at the interface to create the wedge. We observe a significant decrease in the work of adhesion and an increase in equilibrium crack length with an increase in elastic-modulus and thickness of the PDMS elastomer samples. We present and discuss the effect of modulus and specimen-thickness on the adhesion behavior of PDMS elastomer against glass slide.