Engineering rod-coil copolymers nano-objects as Pickering Emulsifiers by dynamic covalent approach

Rod-coil copolymer amphiphiles show interesting self-assembly behaviors and promising application potential, whereas the development of them with controllable amphiphilicity is still challenge. Alternatively, rod-coil copolymer homologues with diversified compositions can be generated conveniently by the dynamic covalent imine approach through altering the molecular structures of amino precursors (A) and aldehyde precursors (D m ). In this work, a family of dynamic covalent imine rod-coil copolymers (D m -A) were generated in water in situ at the constant -NH 2 /-CHO molar ratio of 1 by employing phenyl, biphenyl, terphenyl and tetraphenylethylene based aromatic amines as A and block copolymer poly( N -(2-methacryloylxy) ethyl pyrrolidone)- b -poly(4-(formaldehyde) phenyl methacrylate) (PNMP 72 - b -PBFMA m , m = 3, 13 and 24) as D m , respectively. Moreover, the molecular effects of different precursors on the self-assembly and emulsification behaviors of rod-coil copolymers D m -As were studied systematically. Spherical micelles are the preferred morphologies nearly for all the generated D m -As, except the one generated by D 24 and 4-amino- p -terphenyl (TPA). Alternatively, long and entangled wormlike micelles become favorable attributing to the strong hydrophobic interactions. All D m -A micelles show excellent emulsification in the dodecane/water systems and favor the formation of O/W emulsions as revealed by the confocal laser scanning microscopy (CLSM) method. The interfacial compositions of emulsions are mainly determined by D m but slightly by A. In comparison D 13 -As and D 24 -As micelles with D 3 -As micellar emulsifiers with the same A, the former ones commonly favor the formation of structurally well-defined Pickering emulsions with relatively larger sizes and high fluorescent contrasts between the interfacial layers and dispersed oil droplets. This is because D m -As with the larger m not only have the longer hydrophobic tails but also combine more precursors A as the hydrophobic parts. Both factors enhance the hydrophobic interactions within micelles, endowing D m -A micelles with better anti-shear stability to favor the formation of Pickering emulsions.