Structural changes in self-assembled monolayers induced by photodimerization: A scanning force microscopy investigation

Evidence of photodimerization induced positional order in self-assembled mo nolayers (SAMs) is reported. Scanning force microscopy studies of SAMs of a n alkylsilane with an olefinic group on a silicon surface show that the ter minal alkyl chains are initially disordered but become highly ordered upon irradiation with UV light. Development of the crystalline order in the SAMs is accompanied by changes in frictional properties.