Poly(N-2-(methacryloyloxy)ethyl pyrrolidone)-poly(benzyl methacrylate) diblock copolymer nano-objects via RAFT alcoholic dispersion polymerisation in ethanol. (5th December 2016)

• Record Type: Journal Article
• Authors: Cunningham, Victoria J.; Ning, Yin; Armes, Steven P.; Musa, Osama M.
• Is Part Of: Polymer. Volume 106(2016)
• Page Start: 189
• Page End: 199
• Publication Date: 2016-12-05
• Subjects: Block copolymer nanoparticles -- Dispersion polymerisation -- Polymerisation-induced self-assembly; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2016.07.072
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: N -2-(methacryloyloxy)ethyl pyrrolidone (NMEP) is a highly polar monomer that is much more readily copolymerised with methacrylic monomers than its structural analogue, N -vinyl pyrrolidone. The RAFT solution polymerisation of NMEP has been conducted in ethanol at 70 °C while varying the degree of polymerisation (DP) from 70 to 400. Reducing the CTA/initiator molar ratio from 10.0 to 3.0 when targeting PNMEP100 led to a three-fold rate enhancement and increased the final monomer conversion from 72% to 98%. Targeting DPs of 200 or greater led to lower monomer conversions. DMF GPC analysis of a series of PNMEPx homopolymers confirmed a linear increase in molecular weight with conversion and relatively low dispersities (Mw /Mn < 1.26). A PNMEP50 macro-CTA was chain-extended with benzyl methacrylate (BzMA) via RAFT alcoholic dispersion polymerisation. High BzMA conversions (>90%) were obtained and electron microscopy studies indicated that a range of diblock copolymer morphologies, e.g. spheres, worms and vesicles, were produced by polymerisation-induced self-assembly (PISA). Finally, a PNMEP47 -PBzMA243 diblock copolymer was synthesised via a convenient 'one-pot' protocol whereby a PNMEP47 macro-CTA was first prepared at 97% conversion, followed by in situ RAFT dispersion polymerisation of BzMA to produce diblock copolymer nano-objects. TEM analysis of aliquots taken during the diblock copolymer synthesis indicated a gradual evolution in copolymer morphology from spherical micelles after 1 h to a pure vesicle phase after 8 h via intermediate mixed phases (including worms). Graphical abstract: Highlights: RAFT alcoholic dispersion polymerisation of benzyl methacrylate in ethanol. Polymerisation-induced self-assembly produces spheres, worms or vesicles. One-pot synthesis of amphiphilic diblock copolymer nanoparticles in ethanol.