Quantifying non-gaussian character of motion of polymer fragments during degradation of hydrogels

Via mesoscale simulations, we characterize the process of photo-controlled degradation of spherical nanogels in a good solvent. We show that degradation can be used to dynamically tailor size, shape, and transport properties of these soft particles. We use Dissipative Particle Dynamics (DPD) approach with an adapted form of the modified Segmental Repulsive Potential (mSRP). To characterize degradation process, we track the structural and dynamic characteristics of the remnant nanogel and distribution of the broken-off fragments. To quantify spatial fluctuations in local dynamic behavior, we calculate the self-part of van-Hove correlation function for the network junction points and that for the reactive beads forming degradable bonds. We demonstrate large deviations from the Gaussian behavior during the degradation process. Further, we quantify variations in non-Gaussian character with the extent of degradation reaction for nanogel particles of various sizes and crosslink densities. Our study provides insights into using controlled degradation to dynamically tune shapes and transport properties of hydrogel nanocarriers.