One-pot synthesis of micron-sized polybetaine particles; innovative use of supercritical carbon dioxide. Issue 31 (12th July 2017)

• Record Type: Journal Article
• Authors: Bassett, Simon P.; Birkin, Natasha A.; Jennings, James; Chapman, Emma; O'Reilly, Rachel K.; Howdle, Steven M.; Willcock, Helen
• Is Part Of: Polymer chemistry. Volume 8:Issue 31(2017)
• Page Start: 4557
• Page End: 4564
• Publication Date: 2017-07-12
• Subjects: Polymers -- Periodicals; Macromolecules -- Periodicals; Polymerization -- Periodicals; 547.705
• DOI: 10.1039/c7py00455a
• Languages: English
• ISSNs: 1759-9954

Abstract

Abstract : Well defined micron-sized polybetaine particles have been synthesised for the first time by precipitation polymerisation in a scCO2 /methanol mixture. Abstract : Polybetaines exhibit unique properties combining anti-polyelectrolyte and low protein fouling behaviour, as well as biocompatibility. To date, the synthesis of polybetaine particles >50 nm has proved to be extremely challenging with standard emulsion and dispersion techniques being unsuccessful. Here we present the first reported synthesis of micron-sized, discrete cross-linked polybetaine particles, using polymerisation in scCO2 with methanol as a co-solvent. Discrete particles are produced only when the methanol is efficiently removed in situ using scCO2 extraction. A relatively high crosslinking agent initial concentration (10 wt%) was found to result in the most well defined particles, and particle integrity reduced as the crosslinking agent initial concentration was decreased. A monomer loading of between 3.0 × 10 −2 mol L −1 and 1.8 × 10 −1 mol L −1 resulted in discrete micron sized particles, with significant agglomoration occuring as the monomer loading was increased further. A spherical morphology and extremely low size dispersity was observed by SEM analysis for the optimised particles. The particles were readily re-dispersed in aqueous solution and light scattering measurements confirmed their low size dispersity.