Efficient Synthesis of Amine-Functional Diblock Copolymer Nanoparticles via RAFT Dispersion Polymerization of Benzyl Methacrylate in Alcoholic Media
Efficient Synthesis of Amine-Functional Diblock Copolymer Nanoparticles via RAFT Dispersion Polymerization of Benzyl Methacrylate in Alcoholic Media
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DOI：
10.1021/ma300898e
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发表时间：
2012-06-26
期刊：
影响因子：
5.5
通讯作者：
Armes, Steven P.
中科院分区：
文献类型：
--
作者：
Jones, Elizabeth R.;Semsarilar, Mona;Armes, Steven P.
甲基丙烯酸苄酯（BzMA）通过可逆加成断裂链转移（RAFT）化学在醇分散聚合条件下在乙醇中使用聚（甲基丙烯酸2-（二甲氨基）乙酯）（PDMA）链转移剂（CTA）在70 ℃下聚合。原则上，聚合诱导的自组装可以导致形成球形胶束、蠕虫状胶束或囊泡，其中优选的形态由PDMA PBzMA二嵌段共聚物链的亲水/疏水平衡决定。通过1H-1 NMR研究判断，通常在24小时内获得非常高的单体转化率（>99%）。此外，THF GPC分析证实，实现了相对低的多分散性（M-w/M-n < 1.30），表明相当好的假生命特征。使用PDMA（31）macro-CTA通过系统地改变PBzMA嵌段的目标聚合度和反应溶液的总固体浓度来构建详细的相图。该相图可用于可靠地预测产生纯相而不仅仅是混合相（例如，球体加蠕虫或蠕虫加囊泡）。最后，这些PDMA-PBzMA二嵌段共聚物纳米颗粒保持胶体稳定时，从乙醇转移到水中;水性电泳研究证实，由于PDMA稳定剂链的质子化，颗粒在pH 7以下获得明显的阳离子特性。
Benzyl methacrylate (BzMA) is Polymerized via reversible addition fragmentation chain transfer (RAFT) chemistry under alcoholic dispersion polymerization conditions in ethanol using a poly(2-(dimethylamino)ethyl methacrylate) (PDMA) chain transfer agent (CTA) at 70 degrees C. In principle, polymerization-induced self-assembly can lead to the formation of either spherical, micelles, wormlike micelles, or vesicles, with the preferred morphology being dictated by the hydrophilic hydrophobic balance Of the PDMA PBzMA diblock copolymer chains. Very high monomer conversions (>99%) are routinely obtained within 24 h as judged by H-1 NMR studies. Moreover, THF GPC analyses confirmed that relatively low polydispersities (M-w/M-n < 1.30) are achieved, indicating reasonably good pseudoliving character. A detailed phase diagram was constructed using a PDMA(31) macro-CTA by systematically varying both the target degree of polymerization of the PBzMA block and the total solids concentration of the reaction solution. This phase diagram can be used to reliably predict the synthesis conditions required to produce pure phases, rather than merely mixed phases (e.g., spheres plus worms or worms plus vesicles). Finally, these PDMA-PBzMA diblock copolymer nanoparticles remain colloidally stable when transferred from ethanol into water; aqueous electrophoresis studies confirmed that the particles acquire appreciable cationic character below pH 7 due to protonation of the PDMA stabilizer chains.