Secondment to the Max Planck Institute for Polymer Research
Airit Agasty participated in the secondment at the Max Planck Institute for Polymer Research. The main aim of the lab visit was to show the applicability of universal model of viscosity developed in the team of Professor Holyst, across different macroscopic variables for different polymer systems. Previously, such a model was built on the basis of measured viscosity of polydimethylosiloxane (PDMS) in ethyl acetate in a wide range of polymer concentrations: from dilute up to highly concentrated solutions. The relationship between viscosity and diﬀerent polymer parameters in solution such as coil size, correlation length ξ and such were established experimentally as a function of concentrations, temperature [in a range 283-303 K], and molecular masses. In the present year, further experiments were carried out on 3 more polymer-solvent systems and include the consideration of polydispersity effects from commercial samples. In the end, a complete model is available, which works on small probes experiencing nanoviscosity, as well as for characterizing different polymer systems across a wide range of consolidated variables. One set of results have been compiled as a manuscript – Agasty, A., Wisniewska, A., Kalwarczyk, T., Koynov, K. and Holyst, R., “Scaling equation for the viscosity of polydimethylsiloxane in ethyl acetate: From dilute to concentrated solutions”, Polymer.
The next step of the work was the analysis of the recent study by Wong, William SY, et al. "Adaptive Wetting of Polydimethylsiloxane." Langmuir (2020). Different characteristics of such crosslinked PDMS (SYLGARD®184 from Dow corning) were investigated. Perylene dyes mixed with the two-part crosslinking mix were used to study under confocal microscopy in varying conditions, and the resultant spectroscopic results were analyzed to obtain information about the homogeneity and for oligomer enrichment at water-wetted interfaces.
1 Nov. 2019 - 31 Oct. 2020