title: Incorporating Diblock Copolymer Nanoparticles into Calcite Crystals: Do Anionic Carboxylate Groups Alone Ensure Efficient Occlusion?
abstract: New spherical diblock copolymer nanoparticles were synthesized via RAFT aqueous dispersion polymerization of 2-hydroxypropyl methacrylate (HPMA) at 70 °C and 20% w/w solids using either poly(carboxybetaine methacrylate) or poly(proline methacrylate) as the steric stabilizer block. Both of these stabilizers contain carboxylic acid groups, but poly(proline methacrylate) is anionic above pH 9.2, whereas poly(carboxybetaine methacrylate) has zwitterionic character at this pH. When calcite crystals are grown at an initial pH of 9.5 in the presence of these two types of nanoparticles, it is found that the anionic poly(proline methacrylate)-stabilized particles are occluded uniformly throughout the crystals (up to 6.8% by mass, 14.0% by volume). In contrast, the zwitterionic poly(carboxybetaine methacrylate)-stabilized particles show no signs of occlusion into calcite crystals grown under identical conditions. The presence of carboxylic acid groups alone therefore does not guarantee efficient occlusion: overall anionic character is an additional prerequisite.
authors.affiliation: Department of Chemistry, University of Sheffield , Brook Hill, Sheffield, South Yorkshire S3 7HF, United Kingdom.
authors.forename: Yin
authors.initials: Y
authors.lastname: Ning
authors.affiliation: Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, United Kingdom; The School of Materials, University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom.
authors.forename: Lee A
authors.initials: LA
authors.lastname: Fielding
authors.affiliation: Department of Chemistry, University of Sheffield , Brook Hill, Sheffield, South Yorkshire S3 7HF, United Kingdom.
authors.forename: Kay E B
authors.initials: KE
authors.lastname: Doncom
authors.affiliation: Department of Chemistry, University of Sheffield , Brook Hill, Sheffield, South Yorkshire S3 7HF, United Kingdom.
authors.forename: Nicholas J W
authors.initials: NJ
authors.lastname: Penfold
authors.affiliation: School of Chemistry, University of Leeds , Woodhouse Lane, Leeds LS2 9JT, United Kingdom.
authors.forename: Alexander N
authors.initials: AN
authors.lastname: Kulak
authors.affiliation: Department of Polymer Chemistry, Kyoto University , Kyoto 615-8510, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Matsuoka
authors.affiliation: Department of Chemistry, University of Sheffield , Brook Hill, Sheffield, South Yorkshire S3 7HF, United Kingdom.
authors.forename: Steven P
authors.initials: SP
authors.lastname: Armes