Nanoscale structure and dynamics of thermoresponsive single-chain nanoparticles investigated by EPR spectroscopy

Roos, A.H.. et. al. Soft Matter, 2021, 17, 7032-7037,

We characterize temperature-dependent macroscopic and nanoscopic phase transitions and nanoscopic pre-transitions of water-soluble single chain nanoparticles (SCNPs). We analyze the temperature-dependent phase transitions of spin-labeled SCNPs by rigorous spectral simulations of series of multicomponent EPR-spectra that derive from the nanoinhomogeneities 1) that are due to the single-chain compartmentation in SCNPs and 2) the transformation upon temperature change due to the LCST behavior. Especially for one SCNP, we find an interesting behavior that we ascribe to properties of the nanosized inner core with continuous effects before and jump-like changes after the macroscopic thermal collapse, indicating highly efficient desolvation and compaction upon increase in temperature and aggregation of individual nanoparticles above the collapse temperature. Published with a permission of the Soft Matter 2021.