Novel clickable and fluorescent poly(siloxane amine)s for reusable adhesives and reprocessable elastomers

Abstract

Silicon-containing polymers are valuable organic/inorganic polymers with unique physical and chemical properties. Although silicon element ranks as the second most abundant element in the Earth's crust, there are currently limited varieties of silicon-containing polymers, especially functional ones. Herein, the first examples of a new class of organic–inorganic hybrid poly(siloxane amine)s are presented, which consist of alternating siloxane and amine units. Amine–epoxy polymerization of 1,3-bis(3-glycidyloxypropyl)tetramethyldisiloxane with diverse amines provides facile access to well-defined polymers under mild conditions. Thanks to the abundance of functional amines available in nature and industry, we could obtain poly(siloxane amine)s with various pendant groups in a one-pot manner, which enables further clickable post-functionalization. Unconventional fluorescence and low T_g values were observed due to the unique Si–N coordination and good flexibility of the siloxane backbones, respectively. Via dynamic covalent crosslinking, these polymers have been further demonstrated as valuable building blocks for reusable adhesives and reprocessable elastomers with malleability and recyclability. These functional poly(siloxane amine)s promise a new type of silicon-containing polymer and will be potentially applicable in materials and biological fields.