Interferometric Technique To Determine the Dynamics of Polymeric Fluids under Strong Confinement

CENCHA, LUISA G.; URTEAGA, RAUL; BERLI, CLAUDIO L. A.

MACROMOLECULES

AMER CHEMICAL SOC

Año: 2018

0024-9297

This work presents a new technique to studypolymers under strong geometrical confinement in nanoporousfilms. The procedure is based on sensing the changesof the optical properties of the porous matrix due to polymerimbibition into the pores by using optical interferometry. Asimple theoretical model is used to correlate the timedependentoptical thickness of the film with the polymerdynamics as a function of temperature. To test the methodapplicability, the imbibition of ethyl vinyl acetate in poroussilicon membranes was studied. A large variation of thepolymer viscosity was measured by varying the temperaturefrom 20 to 110 °C. In addition, the confinement degree wasvaried in about 2 orders of magnitude by using matrices withdifferent pore radius. A remarkable decrease in the viscosity was observed when the mean pore radius was reduced. Moreover,the interferometric technique enables the study of very low molecular weight polymers as well as measuring along a wide rangeof temperatures in a single nondestructive experiment.