Shear of telechelic brushes

The forces between two surfaces bearing solvated, telechelic polymer chains (terminated at both ends with a dipolar group) exhibit a clear attractive regime. The range and magnitude of this attraction indicate the presence of multimers on each surface, and the formation of entropically favored bridges between them as the telechelic layers overlap. On sliding the surfaces a shear force close to that expected from the stretching of the polymer bridges is observed, suggesting that the frictional forces can be tuned by varying the interaction strength of the telechelic end groups.