Dilational creep compliance in Langmuir polymer films

Creep compliance is a simple rheological tool to study flow properties in soft matter. As a proof of concept we have studied the dilational flow of Langmuir films made of poly(vinylacetate), a model flexible polymer. The creep response has been probed at different stresses, pointing out the existence of compliance features. The compliance curves are characterized by an exponential-like primary creep followed by a secondary steady-flow regime characterized by a constant strain rate. The phenomenological parameters are found to exhibit power-law behavior on the applied stress.