In situ synthesis of diblock copolymer nano-assemblies via dispersion RAFT polymerization induced self-assembly and Ag/copolymer composite nanoparticles thereof†,Polymer Chemistry

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In situ synthesis of diblock copolymer nano-assemblies via dispersion RAFT polymerization induced self-assembly and Ag/copolymer composite nanoparticles thereof†
Polymer Chemistry ( IF 4.1 ) Pub Date : 2018-02-05 00:00:00 , DOI: 10.1039/c7py01905j
Mengting Tan _{1,

2,

3,

4} , Yan Shi _{1,

2,

3,

4} , Zhifeng Fu _{1,

2,

3,

4} , Wantai Yang _{1,

2,

3,

4}

Affiliation

One pot in situ preparation of poly(acrylic acid)-block-polystyrene (PAA-b-PSt) or poly(acrylic acid)-block-poly(acrylic acid-ran-styrene) (PAA-b-P(AA-r-St)) diblock copolymer nano-objects with multiple morphologies was developed through dispersion RAFT polymerization in ethanol/water mixtures mediated by hydrophilic poly(acrylic acid) (PAA)-based macromolecular RAFT agents. The polymerization shows characteristic features of “living”/controlled radical polymerization and the experimental results are confirmed by transmission electron microscopy (TEM), gel permeation chromatography (GPC), dynamic light scattering (DLS) and ¹H NMR. The effects of various parameters including the monomer conversion, St/AA feed ratio and solvent composition on the morphologies of PAA-b-PSt diblock copolymer nano-objects were investigated in detail. A faster polymerization rate was observed with increasing content of water in mixture solvents, and three stages with two clear turning points at which the rate was enhanced were observed during the polymerization process. Spherical micelles, worms, vesicles, and lacunal nanospheres have been obtained for PAA-b-PSt with the extension of the PSt block in 70/30, 80/20 and 90/10 w/w ethanol/water mixtures. Our results demonstrate that the interesting lacunal morphology of PAA-b-PSt diblock copolymer assembly can be successfully prepared and tuned at high styrene conversion. More interestingly, the residual AA, which was introduced to prepare the random P(AA-r-St) block, can promote the evolution of the copolymer aggregate morphology from spherical micelles to worms and pure vesicles in 90/10 and 80/20 w/w ethanol/water mixtures. The copolymerization of the residual hydrophilic monomer can be a convenient and effective method to tune the morphology and size of the block copolymer aggregates via polymerization-induced self-assembly (PISA). Finally, the in situ formation of silver/polymer composite nanoparticles was demonstrated, suggesting excellent applications in catalysis.

中文翻译：

通过分散RAFT聚合诱导的自组装及其Ag /共聚物复合纳米粒子原位合成二嵌段共聚物纳米组装体†

一锅原位-聚制备（丙烯酸）嵌段-聚苯乙烯（PAA- b -pst）或聚（丙烯酸） -嵌段-聚（丙烯酸- RAN -苯乙烯）（PAA- b -P（AA- ř -St））具有多种形态的二嵌段共聚物纳米物体是通过在亲水性聚丙烯酸（PAA）基大分子RAFT介导的乙醇/水混合物中进行分散RAFT聚合反应而开发的。聚合反应表现出“活性” /受控自由基聚合反应的特征，实验结果通过透射电子显微镜（TEM），凝胶渗透色谱（GPC），动态光散射（DLS）和¹证实。1 H NMR。详细研究了单体转化率，St / AA进料比和溶剂组成等各种参数对PAA- b -PSt二嵌段共聚物纳米物体形态的影响。随着混合溶剂中水含量的增加，聚合速度加快，在聚合过程中观察到三个阶段，两个明显的转折点提高了聚合速度。对于PAA- b -PSt，已经获得了球形胶束，蠕虫，囊泡和腔纳米球，并且在70 / 30、80 / 20和90/10 w / w的乙醇/水混合物中延伸了PSt嵌段。我们的结果表明，PAA- b的有趣的腔状形态-PSt二嵌段共聚物的组装可以成功地制备并在高苯乙烯转化率下进行调节。更有趣的是，被引入以制备无规P（AA- r -St）嵌段的残留AA可以促进共聚物聚集体形态从球形胶束到蠕虫和纯囊泡在90/10和80/20 w内演化。 / w乙醇/水混合物。残留亲水性单体的共聚可以是一种方便有效的方法，可通过聚合诱导的自组装（PISA）调节嵌段共聚物聚集体的形态和尺寸。最后，银/聚合物复合纳米粒子的原位形成得到证明，表明在催化方面的优异应用。

更新日期：2018-02-05

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