LAUSR

Abstract Due to various industrial applications, aqueous foams stabilized by surfactants in combination without and with polymers, biopolymers or/and solid particles have been extensively investigated. In contrast, there are few reports involved in surfactant-free aqueous foams. Herein, a surfactant-free foam system containing xanthan-based amphiphilic polysaccharide (C8-g-XG) and nanosilica particle was presented and studied. With an attempt to address the framework, C8-g-XG was prepared via n-octylamine grafted onto xanthan gum (XG). C8-g-XG inherited good viscosification, salt tolerance and temperature resistance from XG, and lower values of γCMC (39.2 mN/m) appeared in C8-g-XG solutions. Additionally, the surface tension of C8-g-XG solutions (3000 mg/L) with 0.2 wt% nanosilica particles would not change significantly. However, C8-g-XG@nanosilica particle-stablized foams exhibited excellent thermal adaptability, thermal stability and proppant suspension ability due to synergy of C8-g-XG and nanosilica particles. As a result, this strategy may be used to develop eco-friendly low formation-injury foam fluids for hydraulic fracturing application because C8-g-XG could be degraded and its surface activity was disabled.