Dynamics in adsorbed homopolymer layers: Understanding complexity from simple starting points

Now more than ever, smart material interfaces in a variety of applications demand control over complex interfacial processes, often involving adsorbed polymers. To this end, this opinion article addresses the dynamic complexity in homopolymer layers adsorbed at liquid-solid interfaces, summarizing some of the simplest examples and examining the potential impact of specific complicating mechanisms: The distinction between diffusion limited (in free solution) and surface-controlled chain release is made, and then for the latter, several different cases of single-exponential desorption, self-exchange, and displacement are compared: Though the systems present great chemical variety, they have either a limited number of or a weak energy of segment-surface contacts. Increasing the strength and/or numbers of these contacts complicates dynamics, as does increasing molecular weight which can introduce chain pinning.