Study of surface roughness modulation on the adhesion behavior of PDMS elastomer

Abstract: Adhesion control at the interface of two surfaces is crucial in various applications, including the design of micro- and nanodevices such as microfluidic devices, triboelectric nanogenerators, biochips, and electronic sensors. Several factors influence adhesion, including sample preparation, surface energy, mechanical properties such as modulus of elasticity, and surface texture or roughness. This study specifically investigates the effect of surface roughness on the adhesion behavior of the elastomer polydimethylsiloxane (PDMS), focusing on a complementary interface with identical roughness. To create surface roughness, sandpapers with grit sizes ranging from N = 120 to N = 2000 were used during the molding process. The surface roughness of the PDMS elastomer was then characterized using a stylus profilometer. Interfacial adhesion was evaluated through wedge test experiments, which enabled the analysis of the relationship between surface roughness, work of adhesion, and equilibrium crack length. Furthermore, the study also explores the correlation between the real area of contact and the work of adhesion.