Facile hydrophilic modification of polydimethylsiloxane-based sponges for efficient oil–water separation

In this study, an eco-friendly fabrication process for the hydrophilic polydimethylsiloxane (PDMS)-based sponge was proposed with the assistance of sugar templates and poly(dimethylsiloxane-b-ethylene oxide) (PDMS-b-PEO) block copolymer additives. The effects of sugar loadings and sugar particle sizes on sponge structure and separation performance were investigated. Manipulating sugar loadings exhibited a unique control over the porosity of sponge, which further influenced the absorption capacity and oil–water separation speed. Additionally, the surface modification of PDMS sponge from hydrophobic/oleophilic to hydrophilic/underwater oleophobic was achieved by incorporating PDMS-b-PEO. Such modified sponge demonstrated an underwater oil contact angle of 154° and a stable separation efficiency greater than 99.9% in the gravity-driven cycled filtration tests. The hydrophilic PDMS-b-PEO modified sponges highlighted herein reveal a promising potential for novel separation materials with energy-efficient and cost-effective features, which are ideal for oil spill clean-up events and wastewater treatment application.