2024/10/03 by José Muñetón-Díaz, Chi Zhang, Muñetón-Díaz, José +5
Physics and Astronomy · #FOS: Physical sciences #Orbital Angular Momentum in Optics #Soft Condensed Matter (cond-mat.soft)
paper · pdf · doi:10.48550/arxiv.2410.02641
openalex publication_date 2024/10/03 · openalex created_date 2024/10/30 · openalex updated_date 2026/07/28
We experimentally study the pairwise interactions between poly(N-isopropylacrylamide) (pNIPAM) microgel particles using line optical tweezers. To measure their interaction potentials under controlled conditions, we trap two microgel particles in the tweezer and analyze their thermal positional fluctuations near contact. The pair interaction potential is modeled using a Hertzian core polymer brush corona framework, capturing the complexity of particle interactions by accounting for both the deformable, elastic core and the steric effects of the polymer brush-like shell. Our experimental results demonstrate that the brush corona interactions soften as the system approaches the lower critical solution temperature (LCST) of the microgels, consistent with the decay of the polymer's second virial coefficient.