Sol–gel preparation, microstructure and luminescence of rare earth/silica/polyacrylamide hybrids through double functionalized covalent Si–O linkage

Abstract

A new type of photoactive macromolecule hybrid materials have been synthesized with covalent bond linking organically modified Si–O and polymer chains through sol–gel technology. The photoactive center consists of a rare earth (Eu,Tb)-functional silane precursor HIPASi of which 5-hydroxyisophthalic acid (HIPA) is grafted by 3-(triethoxysilyl)-propyl isocyanate (TEPIC). An organic polymer chain (PAMSi), from the polymerization of the precursor AM–Si originated from acrylamide monomer (AM) modified by(3-chloropropyl)trimethoxysilane (CPMS), is introduced with Si–O covalent bond to HIPASi. The resulting hybrids possess a homogeneous and regular microstructure without phase separation phenomena, whose particle sizes decreased with the enhancement of organic polymer component (PAM) content. The luminescence lifetimes, quantum efficiencies and energy transfer efficiencies of the hybrid materials are improved with an increase in the molar ratio of the organic polymer unit, suggesting that the organic polymers are favorable for the luminescence for the template effect of organic chain.