Gels from self-confined emulsion droplets constructed by structurally modified polydimethylsiloxanes

Emulsion gels (EGs), combined the advantages of both emulsions and gels, have attracted much attention in colloid chemistry. However, the preparation of EGs is usually complicated, which greatly hinders their development. Herein, we prepared a polydimethylsiloxane (PDMS) derivative which bears poly (ethoxylated ether) (PEO) segments at the ends and a few alkylamine groups on the side (denoted as AESi hereafter). When being mixed with an acidic amino acid (glutamic acid, Glu) in water, the amine groups of AESi were protonated, leading to an abrupt increase of its solubility. The AESi/Glu complex acts as a supramolecular amphiphile, which can form capsules in water. It can also stabilize excess AESi to form self-confined emulsions. In high loading of AESi, the emulsion droplets stack closely to form highly stable EGs. The EGs possess good viscoelasticity and are tunable by changing temperature or adding inorganic salts. By performing control experiments, structural features of the PDMS derivative and organic acid needed for the construction of EGs have been clarified. The strategy presented in this study provides new opportunity for the preparation and applications of EGs.