Photocontrol over the disorder-to-order transition in thin films of polystyrene-block-poly(methyl methacrylate) block copolymers containing photodimerizable anthracene functionality.
Photocontrol over the disorder-to-order transition in thin films of polystyrene-block-poly(methyl methacrylate) block copolymers containing photodimerizable anthracene functionality.
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DOI：
10.1021/ja2036964
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发表时间：
2011-10
影响因子：
15
通讯作者：
Wei Chen-;Jia-Yu Wang;Wei Zhao;Le Li;Xinyu Wei;A. Balazs;K. Matyjaszewski;T. Russell
中科院分区：
文献类型：
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作者：
Wei Chen-;Jia-Yu Wang;Wei Zhao;Le Li;Xinyu Wei;A. Balazs;K. Matyjaszewski;T. Russell
嵌段共聚物（bcp）从无序状态到有序状态的有序转变，即无序到有序转变（DOT）的可逆光控制，可用于通过光梳理在宏观距离上自组装bcp中创建远程有序纳米结构，类似于用于生产高纯度大单晶的经典区域精炼。在这里，我们设计并合成了含有氘化聚苯乙烯（d(8)-PS）和聚甲基丙烯酸甲酯（PMMA）嵌段的蒽功能化三bcp，以及被蒽随机功能化的聚2-羟乙基甲基丙烯酸酯（PHEMA）中间短嵌段。该三bcp保持了其母体d(8)-PS-b-PMMA双bcp的有序-无序过渡型相行为。在365 nm紫外光照射下，d(8)-PS和PMMA嵌段之间通过蒽光二聚体发生光偶联，导致3 - bcp总分子量显著增加。因此，当三bcp处于相混合状态，但靠近有序跃迁边界时，它会发生DOT，这是由小角中子散射和透射电子显微镜所证明的。利用蒽的光二聚化和热解离作用，可以在薄膜上可逆地通过DOT。目前，蒽基功能化的d(8)-PS-b-PMMA BCP是光梳理过程中最有希望以无创方式在宏观距离上促进远距离横向有序纳米结构的候选者之一。
Reversible photocontrol over the ordering transition of block copolymers (BCPs) from a disordered state to an ordered state, namely the disorder-to-order transition (DOT), can be used to create long-range ordered nanostructures in self-assembled BCPs over macroscopic distances by photocombing, similar to the classic zone refining used to produce highly pure, large single crystals. Here, we have designed and synthesized an anthracene-functionalized tri-BCP containing deuterated polystyrene (d(8)-PS) and poly(methyl methacrylate) (PMMA) blocks, as well as a short middle block of poly(2-hydroxyethyl methacrylates) (PHEMA) that is randomly functionalized by anthracene. This tri-BCP maintains the order-to-disorder transition-type phase behavior of its parent d(8)-PS-b-PMMA di-BCPs. Under 365 nm UV irradiation, the junction between d(8)-PS and PMMA blocks is photocoupled through the anthracene photodimers, leading to a significant increase in the total molecular weight of the tri-BCP. As a consequence, when the tri-BCP is phase-mixed but close to the boundary of the ordering transition, it undergoes the DOT, as evidenced by small-angle neutron scattering and transmission electron microscopy. The tri-BCP could be reversibly brought through the DOT in thin films by taking advantage of photodimerization and thermal dissociation of anthracene. Currently, anthracene-functionalized d(8)-PS-b-PMMA BCP is one of the most promising candidates for the photocombing process to promote long-range laterally ordered nanostructures over macroscopic distances in a noninvasive manner.