Probing the influence of composition and cross-linking degree on single-chain nanoparticles from poly(tetrahydrofuran-ran-epichlorohydrin) copolymers: Insights from neutron scattering, calorimetry, and dielectric spectroscopy

The industrial sector has made significant strides in the development of multicomponent and multiphasic polymer materials, including polymer blends, composites (such as nanocomposites), and various copolymers. Random copolymers, characterized by their statistical arrangement of repeating units, are particularly noteworthy due to their tunability from amorphous to semicrystalline states. In this study, we focus on poly(tetrahydrofuran-ran-epichlorohydrin) (P(THF-ran-ECH)) copolymers, which serve as precursors for single-chain nanoparticles (SCNPs). These SCNP-based materials are of particular interest as they bridge the gap between traditional polymers and colloids. This research comprehensively investigates how the type and degree of internal cross-linking influence the structure and dynamics of P(THF-ran-ECH) copolymers and their SCNPs. Techniques such as quasielastic neutron scattering (QENS), differential scanning calorimetry (DSC), and broadband dielectric spectroscopy (BDS) were employed to study copolymers with varying compositions and levels of cross-linking. By analyzing two samples with different epichlorohydrin (ECH) contents (13 mol% and 27 mol%), we aim to control crystallization and explore its effects on dynamic behavior. Our results show that both the composition and the degree of cross-linking significantly impact the dynamics of the SCNPs, with SCNPs exhibiting slower dynamics compared to their precursor copolymers. Furthermore, semicrystalline samples display faster dynamics in SCNPs than amorphous samples. These findings provide valuable insights for the design and optimization of advanced multicomponent polymer systems.