Polyamine‐Functionalized 3D Macroporous Silica One‐Pot Prepared Through Supramolecular Emulsifier Aided Ex‐Situ, Gradient and Directed Growth of Silica

ABSTRACT The functionalization of porous silica with polyamine (typically branched polyethyleneimine (PEI)) usually suffers from drawbacks such as sharply (typically 100‐fold) decreased surface, insufficient and tedious surface functionalization. Here a cost‐effective route which mostly overcomes these drawbacks is presented. Minor glycidyloxypropyltrimethoxysilane (GPTOS) along with major tetraethoxysilane (TEOS) is dispersed in water with the aid of a supramolecular emulsifier of PEI/sodium dodecylbenzene sulfonate (SDBS), and the resulting emulsion directly affords open, PEI‐dictated and 3D macroporous silica after standing and subsequent vacuum drying. The route is featured in that 1) Opening pores afford because of the ex‐situ reaction of silicates; 2) The supramolecular emulsifier is tolerant to the demulsification of reaction‐released alcohols, and allows only the outer PEI shell accessible to silica growth; 3) The silica surface is sufficiently and robustly dictated by nearly monolayer PEI because the preferential evolution of GPTOS allows PEI to be immobilized by a few bonds to the silica framework, leaving most PEI amines intact; 4) the specific surface area of the PEI‐dictated material is about one order higher than a typical and similar product. The as‐prepared macroporous material quickly and efficiently separate water from oil and oil‐in‐water emulsions.