Mechanically flexible, super-hydrophobic and flame-retardant hybrid nano-silica/graphene oxide wide ribbon decorated sponges for efficient oil/water separation and fire warning response

Abstract

Developing porous sponge materials with good mechanical robustness, surface super-hydrophobicity and excellent flame retardancy is strongly needed for various applications, but it challenging to realize these multiple functionalities simultaneously in a facile approach. Herein, we show that a mechanically flexible, super-hydrophobic and flame-retardant functionalized silica/graphene oxide wide ribbon (GOWR) coated melamine sponge (M-GOWR@MF) is fabricated by an extremely simple two-step surface-modifying method. The interconnected GOWR network is decorated onto the MF skeleton via a facile dip-coating approach, followed by the surface modification of n-Octyltriethoxysilane functionalized nano-silica particles. The as-prepared MF sponge composites display super-hydrophobicity/super-oleophilicity and good mechanical robustness, which produce outstanding absorption capacity for both floating and heavy oils from water and efficient continuous oil/water separation performance. Further, the M-GOWR@MF sponge composites also exhibit excellent flame resistance and chemical stability, which can be utilized to construct efficient fire warning sensors for complicated environments. The sensor shows fast danger alarm response of ~3 s when encountering a critical fire risk (e.g. flame source) and stable fire early warning signal at abnormal high temperature (e.g. 39 and 5 s for 300 and 400 °C) even after suffering a large deformation or one-year outdoor use. Based on the structural analysis, the related structure feature and evolution mechanisms during the flame detection and high temperature were discussed and analyzed. Clearly, the hybrid functionalized silica/GOWR network offers a new strategy and paradigm to design of advanced multi-functional polymer sponge composites.