Buksa Hubert, Neal Thomas J, Varlas Spyridon, Hunter Saul J, Musa Osama M, Armes Steven P
Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K.
Ashland Specialty Ingredients, 1005 US 202/206, Bridgewater, New Jersey 08807, United States.
Macromolecules. 2023 Jun 2;56(11):4296-4306. doi: 10.1021/acs.macromol.3c00534. eCollection 2023 Jun 13.
The reversible addition-fragmentation chain transfer (RAFT) aqueous dispersion polymerization of 4-hydroxybutyl acrylate (HBA) is conducted using a water-soluble RAFT agent bearing a carboxylic acid group. This confers charge stabilization when such syntheses are conducted at pH 8, which leads to the formation of polydisperse anionic PHBA latex particles of approximately 200 nm diameter. The weakly hydrophobic nature of the PHBA chains confers stimulus-responsive behavior on such latexes, which are characterized by transmission electron microscopy, dynamic light scattering, aqueous electrophoresis, and H NMR spectroscopy. Addition of a suitable water-miscible hydrophilic monomer such as 2-(-(acryloyloxy)ethyl pyrrolidone) (NAEP) leads to in situ molecular dissolution of the PHBA latex, with subsequent RAFT polymerization leading to the formation of sterically stabilized PHBA-PNAEP diblock copolymer nanoparticles of approximately 57 nm diameter. Such formulations constitute a new approach to reverse sequence polymerization-induced self-assembly, whereby the hydrophobic block is prepared first in aqueous media.
使用带有羧酸基团的水溶性可逆加成-断裂链转移（RAFT）试剂进行丙烯酸4-羟丁酯（HBA）的RAFT水分散聚合。当在pH 8下进行此类合成时，这赋予了电荷稳定性，从而导致形成直径约200 nm的多分散阴离子型聚（丙烯酸4-羟丁酯）（PHBA）胶乳颗粒。PHBA链的弱疏水性赋予此类胶乳刺激响应行为，通过透射电子显微镜、动态光散射、水性电泳和核磁共振氢谱对其进行表征。添加合适的与水混溶的亲水性单体，如2-（-（丙烯酰氧基）乙基）吡咯烷酮（NAEP），会导致PHBA胶乳原位分子溶解，随后的RAFT聚合导致形成直径约57 nm的空间稳定的PHBA-PNAEP二嵌段共聚物纳米颗粒。此类配方构成了一种反向顺序聚合诱导自组装的新方法，即在水性介质中首先制备疏水嵌段。
