The direct synthesis of interface-decorated reactive block copolymer nanoparticles via polymerisation-induced self-assembly
The direct synthesis of interface-decorated reactive block copolymer nanoparticles via polymerisation-induced self-assembly
复制标题
通过聚合诱导自组装直接合成界面修饰的反应性嵌段共聚物纳米粒子
DOI：
10.1039/c5py00656b
复制
发表时间：
2015-01-01
影响因子：
4.6
通讯作者：
Cai, Yuanli
中科院分区：
文献类型：
--
作者：
Jiang, Yanyan;Xu, Na;Cai, Yuanli
两亲性嵌段共聚物在水中的自组装会导致疏水活性基元被包裹在成核嵌段中，这降低了它们作为水催化剂的性能。这个问题可以通过聚合诱导自组装(PISA)来规避。在这里，我们报告了一种新的一锅法合成反应性嵌段共聚纳米粒子的方法，该纳米粒子的疏水活性基元装饰了周围的核-壳界面。我们展示了一种商用专用单体双丙酮丙烯酰胺(DAAM)在25°C可见光照射下的快速RAFT水分散聚合。PISA通过顺序脱水、相分离和反应加速进行聚合，从而在30分钟内实现完全转化。用NH3+-单体取代最小的DAAM会导致核形成块的轻微水化，从而导致所得统计嵌段共聚物的低多分散性。此外，原位自组装和链生长同时有利于新添加的NH3+单元向外调节到核壳界面，而主要的DAAM单元坍塌成疏水的PISA-核。两者都能及时和选择性地自组装成新的反应性纳米颗粒，其NH3+基元装饰着周围的核-壳界面。这些纳米粒子非常适合于制造先进的纳米反应器，其疏水可移动的金属中心通过同时进行亚胺转化和锌(II)配位来装饰周围的界面。这种PISA纳米结构赋予疏水性金属中心一个巨大的和可获得的比表面积，并由水溶性壳层稳定。因此，这一策略在制备金属酶激发的水相催化剂方面具有诱人的潜力。
Self-assembly of amphiphilic block copolymers in water suffers from the undesired encapsulation of hydrophobic reactive motifs in a core-forming block, which deteriorates their performance as aqueous catalysts. This problem can be circumvented by polymerisation-induced self-assembly (PISA). Herein, we report a new strategy for one-pot synthesis of reactive block copolymer nanoparticles whose hydrophobic reactive motifs decorate the surrounding core–shell interfaces. We demonstrate fast RAFT aqueous dispersion polymerisation of a commercially available specialty monomer, diacetone acrylamide (DAAM), under visible light irradiation at 25 °C. PISA is induced by polymerisation via sequential dehydration, phase separation and reaction acceleration, thus achieving complete conversion in 30 min. The replacement of minimal DAAM by an NH3+-monomer induces slight hydration of the core-forming block, and thus a low polydispersity of the resulting statistic-block copolymer. Moreover, simultaneous in situ self-assembly and chain growth favour the adjustment of newly-added NH3+-units outward to core–shell interfaces while the major DAAM units collapse into hydrophobic PISA-cores. Both lead to timely and selective self-assembly into the new reactive nanoparticles whose NH3+-motifs decorate the surrounding core–shell interfaces. These nanoparticles are well-suited for fabrication of advanced nanoreactors whose hydrophobic dative metal centres decorate the surrounding interfaces via simultaneous imine conversion and Zn(II)-coordination. Such PISA-nanostructures endow hydrophobic metal centres with a huge and accessible specific surface area and are stabilized by water-soluble shells. Therefore, this strategy holds fascinating potential for the fabrication of metalloenzyme-inspired aqueous catalysts.