Graduate student Xinru Huang and Prof. Connie Roth demonstrate that chains tethered to substrates at low grafting densities locally increase the glass transition temperature by 50 Kelvin
Roth Lab Research
Profile of Local Glass Transition Temperature Across a Glassy-Rubbery Polymer Interface
Physics PhD graduate student Roman Baglay and Professor Connie Roth have experimentally measured how the local glass transition temperature Tg(z) changes across a polymer-polymer interface between two dynamically dissimilar polymers with an 80 K difference in bulk Tg. Traditionally one would expect the dynamics to follow the sharp 7-nm wide composition profile, but surprisingly the profile in cooperative segmental dynamics is very broad and asymmetric, spanning 350-400 nm from the bulk Tg value of one polymer to the another. These results indicate that cooperative segmental dynamics associated with the glass transition can be perturbed over much longer length scales than every considered.
This research was published as a Communication in the Journal of Chemical Physics: Roman R. Baglay and Connie B. Roth, J. Chem. Phys. 2015, 143, 111101. DOI: http://dx.doi.org/10.1063/1.4931403