Department of Materials Science and Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA.
Department of Materials Science and Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA.; Chemistry Department, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA.
Sci Adv. 2016 Dec 23;2(12):e1601484. doi: 10.1126/sciadv.1601484. eCollection 2016 Dec.
The tethering of ligands to nanoparticles has emerged as an important strategy to control interactions and organization in particle assembly structures. We demonstrate that ligand interactions in mixtures of polymer-tethered nanoparticles (which are modified with distinct types of polymer chains) can impart upper or lower critical solution temperature (UCST/LCST)-type phase behavior on binary particle mixtures in analogy to the phase behavior of the corresponding linear polymer blends. Therefore, cooling (or heating) of polymer-tethered particle blends with appropriate architecture to temperatures below (or above) the UCST (or LCST) results in the organization of the individual particle constituents into monotype microdomain structures. The shape (bicontinuous or island-type) and lengthscale of particle microdomains can be tuned by variation of the composition and thermal process conditions. Thermal cycling of LCST particle brush blends through the critical temperature enables the reversible growth and dissolution of monoparticle domain structures. The ability to autonomously and reversibly organize multicomponent particle mixtures into monotype microdomain structures could enable transformative advances in the high-throughput fabrication of solid films with tailored and mutable structures and properties that play an important role in a range of nanoparticle-based material technologies.
配体与纳米颗粒的连接已成为控制颗粒组装结构中相互作用和组织的重要策略。我们证明，混合聚合物连接的纳米颗粒（用不同类型的聚合物链修饰）中的配体相互作用可以在二元颗粒混合物中赋予上临界溶液温度（UCST）/下临界溶液温度（LCST）型相行为，类似于相应的线性聚合物共混物的相行为。因此，具有适当结构的聚合物连接粒子混合物的冷却（或加热）至低于（或高于）UCST（或 LCST）的温度会导致各个粒子成分组织成单型微区结构。通过改变组成和热过程条件，可以调整粒子微区的形状（双连续或岛型）和长度尺度。通过临界温度对 LCST 粒子刷混合物进行热循环，可以使单粒子域结构的可逆生长和溶解。将多组分粒子混合物自主且可逆地组织成单型微区结构的能力，可能会推动在具有定制和可变化结构和性能的固体薄膜的高通量制造方面取得变革性进展，这些结构和性能在一系列基于纳米粒子的材料技术中起着重要作用。
