ORGS3-0710
Tunable Structure, Relaxation, and Printability of Complex Coacervate Core Hydrogels via Charged-Block Length Asymmetry
Topic
GS3. Graduate Student Oral Session III: Polymer Synthesis, Structure, Properties, and Processing
When and Where
Sep 28, 2026
16:00 - 16:12
Room 103
Presenter(s)
Moon-Chul Ryu (Hongik University)
Co-Author(s)
Abstract
Complex coacervate core hydrogels (C3Hs) are dynamic polymer networks whose viscoelasticity originates from molecular exchange and rearrangement within hydrated ionic cores. However, a simple molecular strategy for programming their relaxation time and processing behavior remains underdeveloped. In this study, we control the structure and dynamics of C3Hs by introducing charged-block length asymmetry into triblock/diblock copolyelectrolyte assemblies. Small-angle X-ray scattering reveals that well-defined coacervate core networks are maintained even when the oppositely charged blocks have unequal lengths. By systematically changing the charged-block length of the diblock component, the coacervate core dimension and terminal relaxation time are tuned over a broad range. The structural evolution is interpreted using a free-energy picture in which short and long charged blocks contribute differently to core packing and chain stretching. Rheological analysis shows that the relaxation time is better described by the population-averaged charged-block length in the core rather than by a single polymer architecture, suggesting that collective junction dynamics dominate stress relaxation. Furthermore, blending short and long diblocks provides a composition-based method to continuously regulate relaxation without changing the triblock backbone or total polymer concentration. This tunable relaxation directly affects extrusion printing, where slower dynamics improve shape retention whereas faster dynamics promote interfilament fusion. These findings establish charged-block length asymmetry as a practical design principle for creating C3Hs with programmable viscoelasticity and printability.
