RAFT synthesis of polyethylene glycol (PEG) and amino-functionalized amphiphilic copolymers for dispersing carbon nanofibers

We designed and synthesized a series of amphiphilic copolymers from poly(ethylene glycol) monoacrylate (PEGMA), 2-(dimethylamino) ethyl methacrylate (DMAEMA), styrene (St), and butyl acrylate (BA) via reversible additionfragmentation chain transfer (RAFT) polymerization. The dispersion capability of carbon nanofibers (CNFs) by these copolymers as well as their stability were investigated using UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), thermogravimetry (TG), transmission electron microscopy (TEM) and dynamic light-scattering (DLS) techniques. The results show that both of the block copolymers PPEGMA- b -P(DMAEMA- co -St- co -BA) and PDMAEMA- b -P(PEGMA- co -PSt- co -PBA) enabled better efficiencies toward dispersion and functionalization of CNFs compared to the random copolymer and P(PEGMA- co -BA)- b -P(DMAEMA- co -St) polymer, which allowed us to evaluate the effect of block sequences on the dispersing properties and understand the structureproperty relationship between CNFs and amino-containing block-copolymers. Quaternary copolymer dispersants containing polyethylene glycol (PEG) and amino side chains were synthesized via RAFT and were used to non-covalently functionalize CNFs.