2025/05/08 by Takarai, Haruki, Yasuda, Takashi, Sakumichi, Naoyuki +1
#Biological Physics (physics.bio-ph) #Chemical Physics (physics.chem-ph) #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Soft Condensed Matter (cond-mat.soft) #Statistical Mechanics (cond-mat.stat-mech)
paper · doi:10.48550/arxiv.2505.05254
The equilibrium partitioning of linear polymer chains into flexible polymer networks is governed by intricate entropic constraints arising from configurational degrees of freedom of both chains and network, yet a quantitative understanding remains elusive. Using model hydrogels with precisely defined network structures, we experimentally reveal a universal law governing linear polymer partitioning into flexible polymer networks. We establish a novel label-free, contactless method to measure partition ratio, based on the increase in osmotic pressure induced by external polymer chains partitioning into the network. Moreover, we find a universal law in which the partition constant is solely determined by the squared ratio (Rg / lcycle)2, where Rg is the gyration radius of the polymer chain and lcycle is the characteristic mesh size of the network, as defined by the cycle length.