Department of Chemical and Biomolecular Engineering, ‡Department of Physics, Korea Advanced Institute of Science and Technology (KAIST) , Daejeon, 305-701 Republic of Korea.
J Am Chem Soc. 2014 Jul 16;136(28):9982-9. doi: 10.1021/ja502075f. Epub 2014 Jul 1.
The tuning of interfacial properties at selective and desired locations on the particles is of great importance to create the novel structured particles by breaking the symmetry of their surface property. Herein, a dramatic transition of both the external shape and internal morphology of the particles of polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) was induced by precise positioning of size-controlled Au nanoparticle surfactants (Au NPs). The size-dependent assembly of the Au NPs was localized preferentially at the interface between the P4VP domain at the particle surface and the surrounding water, which generated a balanced interfacial interaction between two different PS/P4VP domains of the BCP particles and water, producing unique convex lens-shaped BCP particles. In addition, the neutralized interfacial interaction, in combination with the directionality of the solvent-induced ordering of the BCP domains from the interface of the particle/water, generated defect-free, vertically ordered porous channels within the particles. The mechanism for the formation of these novel nanostructures was investigated systemically by varying the size and the volume fraction of the Au NPs. Furthermore, these convex lens-shaped particles with highly ordered channels can be used as a microlens, in which the light can be concentrated toward the focal point with enhanced near-field signals. And, these particles can possess additional optical properties such as unique distribution of light scattering as a result of the well-ordered Au cylinders that filled into the channels, which hold great promise for use in optical, biological-sensing, and imaging applications.
通过在粒子表面的特定和所需位置上调整界面性质，可以在打破其表面性质对称性的情况下创造出新型结构粒子。在此，通过精确定位尺寸可控的金纳米粒子表面活性剂（Au NPs），可以诱导聚苯乙烯-b-聚（4-乙烯基吡啶）（PS-b-P4VP）粒子的外部形状和内部形态发生剧烈转变。Au NPs 的尺寸依赖性组装优先定位于粒子表面的 P4VP 域与周围水之间的界面处，这在 BCP 粒子的两个不同 PS/P4VP 域与水之间产生了平衡的界面相互作用，从而产生了独特的凸透镜形 BCP 粒子。此外，中和的界面相互作用，结合溶剂诱导的从粒子/水界面开始的 BCP 域的定向排列，在粒子内部生成了无缺陷的、垂直有序的多孔通道。通过改变 Au NPs 的尺寸和体积分数，系统地研究了这些新型纳米结构形成的机制。此外，这些具有高度有序通道的凸透镜形粒子可用作微透镜，其中光可以集中在焦点处，增强近场信号。并且，由于填充到通道中的有序 Au 圆柱，这些粒子可以具有独特的光散射分布，这为在光学、生物传感和成像应用中提供了巨大的应用前景。
