Wen Shang-Pin, Trinh Elisabeth, Yue Qi, Fielding Lee A
Department of Materials, School of Natural Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
Henry Royce Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
Langmuir. 2022 Jul 12;38(27):8187-8199. doi: 10.1021/acs.langmuir.2c00327. Epub 2022 Jun 30.
Polymer/graphene oxide (GO) nanocomposite particles were prepared heteroflocculation between 140-220 nm cationic latex nanoparticles and anionic GO nanosheets in either acidic or basic conditions. It is demonstrated that nanocomposite particles can be formed using either poly(2-vinylpyridine)--poly(benzyl methacrylate) (P2VP-PBzMA) block copolymer nanoparticles prepared by reversible-addition chain-transfer (RAFT)-mediated polymerization-induced self-assembly (PISA), or poly(ethylene glycol)methacrylate (PEGMA)-stabilized P2VP latexes prepared by traditional emulsion polymerization. These two latexes are different morphologically as the P2VP-PBzMA block copolymer latexes have P2VP steric stabilizer chains in their corona, whereas the PEGMA-stabilized P2VP particles have a P2VP core and a nonionic steric stabilizer. Nevertheless, both the P2VP-PBzMA and PEGMA-stabilized P2VP latexes are cationic at low pH. Thus, the addition of GO to these latexes causes flocculation to occur immediately due to the opposite charges between the anionic GO nanosheets and cationic latexes. Control heteroflocculation experiments were conducted using anionic sterically stabilized poly(potassium 3-sulfopropyl methacrylate)--poly(benzyl methacrylate) (PKSPMA-PBzMA) and nonionic poly(benzyl methacrylate) (PBzMA) nanoparticles to demonstrate that polymer/GO nanocomposite particles were not formed. The degree of flocculation and the strength of electrostatic interaction between the cationic polymer latexes and GO were assessed using disc centrifuge photosedimentometry (DCP), transmission electron microscopy (TEM), and UV-visible spectrophotometry. These studies suggest that the optimal conditions for the formation of polymer/GO nanocomposite particles were GO contents between 10% and 20% w/w relative to latex, with the latexes containing P2VP in their corona having a stronger electrostatic attraction to the GO sheets.
聚合物/氧化石墨烯(GO)纳米复合颗粒是通过在酸性或碱性条件下,使140 - 220 nm的阳离子乳胶纳米颗粒与阴离子GO纳米片之间发生异相絮凝而制备的。结果表明,纳米复合颗粒既可以使用通过可逆加成链转移(RAFT)介导的聚合诱导自组装(PISA)制备的聚(2 - 乙烯基吡啶)-聚(甲基丙烯酸苄酯)(P2VP - PBzMA)嵌段共聚物纳米颗粒形成,也可以使用通过传统乳液聚合制备的聚(乙二醇)甲基丙烯酸酯(PEGMA)稳定的P2VP乳胶形成。这两种乳胶在形态上有所不同,因为P2VP - PBzMA嵌段共聚物乳胶在其冠层中有P2VP空间稳定剂链,而PEGMA稳定的P2VP颗粒有一个P2VP核和一个非离子空间稳定剂。然而,P2VP - PBzMA和PEGMA稳定的P2VP乳胶在低pH值下都是阳离子性的。因此,由于阴离子GO纳米片与阳离子乳胶之间的相反电荷,向这些乳胶中添加GO会立即导致絮凝发生。使用阴离子空间稳定的聚(3 - 磺丙基甲基丙烯酸钾)-聚(甲基丙烯酸苄酯)(PKSPMA - PBzMA)和非离子聚(甲基丙烯酸苄酯)(PBzMA)纳米颗粒进行对照异相絮凝实验,以证明未形成聚合物/GO纳米复合颗粒。使用圆盘离心光沉降法(DCP)、透射电子显微镜(TEM)和紫外可见分光光度法评估阳离子聚合物乳胶与GO之间的絮凝程度和静电相互作用强度。这些研究表明,形成聚合物/GO纳米复合颗粒的最佳条件是相对于乳胶,GO含量为10%至20% w/w,冠层中含有P2VP的乳胶对GO片具有更强的静电吸引力。