Ning Yin, Fielding Lee A, Doncom Kay E B, Penfold Nicholas J W, Kulak Alexander N, Matsuoka Hideki, Armes Steven P
Department of Chemistry, University of Sheffield , Brook Hill, Sheffield, South Yorkshire S3 7HF, United Kingdom.
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.
ACS Macro Lett. 2016 Mar 15;5(3):311-315. doi: 10.1021/acsmacrolett.6b00022. Epub 2016 Feb 12.
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.
通过在70℃和20% w/w固含量下，以聚（甲基丙烯酸羧酸甜菜碱）或聚（甲基丙烯酸脯氨酸）作为空间稳定剂嵌段，对甲基丙烯酸2-羟丙酯（HPMA）进行可逆加成-断裂链转移（RAFT）水分散聚合，合成了新型球形二嵌段共聚物纳米粒子。这两种稳定剂都含有羧酸基团，但聚（甲基丙烯酸脯氨酸）在pH 9.2以上呈阴离子性，而聚（甲基丙烯酸羧酸甜菜碱）在此pH下具有两性离子特性。当在这两种类型的纳米粒子存在下，方解石晶体在初始pH为9.5的条件下生长时，发现阴离子型聚（甲基丙烯酸脯氨酸）稳定的粒子均匀地包埋在整个晶体中（质量分数高达6.8%，体积分数高达14.0%）。相比之下，两性离子型聚（甲基丙烯酸羧酸甜菜碱）稳定的粒子在相同条件下生长的方解石晶体中没有被包埋的迹象。因此，仅羧酸基团的存在并不能保证有效的包埋：整体的阴离子特性是一个额外的先决条件。
Zotero 插件
