Surface and friction forces between grafted polysaccharide layers in the absence and presence of surfactant

► We study interactions between chemically grafted polysaccharide layers in water. ► We synthesize and graft an end-terminated dextran silane coupling agent to silica. ► A bridging attraction was seen between a silica surface and a polydextran surface. ► Repulsive forces and high friction were seen between two polydextran surfaces. ► Addition of surfactant enhanced the repulsive forces and decreased the friction.