Microsphere Adhesion on Rubber Films Accompanied by Sphere Sedimentation

Abstract

Understanding the adhesion process between a rigid material (filler) and a viscoelastic material is important for designing an enhanced industrial material. However, the adhesion process is not simple because the properties of the adhesive, adherend, and interface are intricately influenced by this process. Here we investigate the adhesion of microspheres onto rubber films to clarify the dominant factor in the adhesion process. A rubber meniscus first forms on the sphere surface, followed by sedimentation of the sphere into the rubber film. This sedimentation is even observed when the surface free energy of the sphere is lower than that of the rubber film, which indicates that the driving force of meniscus formation obeys Young’s equation on a tangential line of the sphere. The dominant factor of the sedimentation behavior is investigated by using atomic force microscopy force–sample deformation curve measurements and creep tests on the rubber films. These experimental results demonstrate that the adhesion process is strongly dominated by the viscoelastic property of the bulk rubber as opposed to the sphere and interface properties.

Imparting scalephobicity with rational microtexturing of soft materials

“…The hydrogel, a compliant hydrophilic coating, with low polymer content showed excellent removal performance for both microfoulants and crystallites. For silicones, there is a possible trade-off of making the coating softer to enhance removal, but excessive compliance can lead to indentation ( 76 ) and lubrication-induced gliding that hinders removal. Introducing microtexture, as has been studied before for rigid materials ( 8 , 36 ), improved the performance of hydrophobic PDMS 10:1 for particulate fouling.…”