Microgel Evolution at Three-Phase Contact Region and Associated Wettability Alteration

Wettability alteration induced by nanoparticle and polymer have a broad application range in the industry and attracts a growing attention. Microgel as a special material with polymer/colloid duality is a potential candidate to initiate wettability alteration though seldom addressed in the field. This work provides direct observation on microgel-induced contact angle change of the sessile oil droplets in a microscopic view. The distribution of fluoresced microgels in the vicinity of the oil/water/solid three-phase contact line (TPCL) has been quantitatively investigated using confocal laser scanning microscopy (CLSM). Slow wettability alteration of the glass substrates towards oil-phobic direction induced by microgels has been demonstrated. The mechanism of microgel induced wettability alteration has been proposed based on the interaction between microgel and TPCL. The findings pave the way for microgel-induced wettability alteration towards enhanced oil recovery (EOR).