Elastic porous organosilica monoliths (POMs) are successfully prepared by water in oil (w/o) high internal phase emulsions (HIPEs) with a novel silica precursor named polyethoxysiloxane (PEOS) as sole stabilizer. The stability of the HIPEs and the mechanical strength of the POMs are investigated as functions of PEOS and crosslinker contents in the oil phase. FESEM reveals that PEOS molecules play a significant role of in situ growth into silica particles to strengthen the POMs, which enables the successful preparation of elastic POM5. Furthermore. oil-water separation behavior of the POM5 is studied. Both the absorbent capacity and speed are considerably superior to the previously reported PDMS sponges. (C) 2020 Elsevier Inc. All rights reserved.