Entropic Origin of Polymer Nucleation at Amorphous Solid Interfaces

Interfaces play a pivotal role in various physical, chemical, and biological processes. In polymer crystallization, nucleation often occurs at solid interfaces due to the reduced barrier for heterogeneous nucleation, with the chain conformations and dynamics deviating significantly from their undisturbed (bulk) state. In this Letter, we employed a nanopore-confined system to differentiate between two nucleation scenarios: surface nucleation and homogeneous nucleation, through comprehensive crystal orientation analysis. Experimental findings reveal that surface-induced nucleation in polymers is predominantly driven by an entropic effect, arising from the loss of conformational entropy as polymer chains flatten at weakly interacting solid interfaces. Homogeneous nucleation is, instead, predominant in cases of strong interfacial interactions.