ELECTRORHEOLOGICAL RESPONSES OF SOFT IONIC COLLOIDS

摘要

N-isopropyl poly acrylamide microgel colloids exhibit strong electric-field-induced phase transitions, suggesting the possibility of a strong electrorheological response. [1] Electrorheological (ER) fluids draw researchers' attention due to their huge potential for applications in mechanical devices, switches, valves and microfluidic chips. [2] In the presence of an external electric field, dispersions of ionic microgels in water show microstructural changes with a complex phase behaviour as a function of volume fraction and electric field amplitude. [3] In this work, we present our first results of an experimental setup to make AC electro-rheology measurements on aqueous dispersions of ionic PNIPAM microgel colloids over a range of particle volume fractions. We will compare the ER response of these soft colloids to more standard dipolar silica colloids.