Electric Field-Induced Structural Transitions in Ionic Microgels Probed by Small-Angle Neutron Scattering

by Dr BRIJITTA JOSEPH BONIFACE (JCNS)

Monday 2 Jun 2025, 14:30 → 15:30 Europe/Berlin

PH HS 3 (Physics Department)

Poly(N-isopropylacrylamide) (PNIPAM) microgels represent a versatile class of soft matter system that provides unique opportunities to investigate cooperative phenomena such as phase transitions, structural ordering, and self-assembly. In this talk, I will present our study on the AC electric field-induced directed assembly of ionic PNIPAM-co-acrylic acid (PNIPAM-co-AAc) microgels from dilute to overcrowded conditions, using small-angle neutron scattering (SANS) in a zero-average contrast (ZAC) solvent. The field-induced response of the microgels was found to vary significantly with cross-linking density. Depending on the electric field strength, we observed transformations such as compression in loosely cross-linked microgels, interpenetration in moderately cross-linked ones, and shape anisotropy in highly cross-linked microgels. These structural adaptations highlight the interplay between microgel elasticity and external fields for designing field-responsive colloidal systems and adaptive soft materials.