Sliding friction at soft micropatterned elastomer interfaces.

In this paper, we present an experimental study of the friction between a smooth elastomer lens and an elastomer substrate micropatterned with hexagonal arrays of cylindrical pillars. Depending on the normal load, the surfaces can be in top or mixed contact. The friction force can be interpreted in terms of friction stresses in the full contact and top contact zones.

Waterborne polyurethane-acrylic hybrid nanoparticles by miniemulsion polymerization: applications in pressure-sensitive adhesives.

Waterborne polyurethane-acrylic hybrid nanoparticles for application as pressure-sensitive adhesives (PSAs) were prepared by one-step miniemulsion polymerization. The addition of polyurethane to a standard waterborne acrylic formulation results in a large increase in the cohesive strength and hence a much higher shear holding time (greater than seven weeks at room temperature), which is a very desirable characteristic for PSAs. However, with the increase in cohesion, there is a decrease in the relative viscous component, and hence there is a decrease in the tack energy.