【作者】 胡慧成； 吉飞； 徐勇； 於佳琪； 刘其鹏； 陈磊； 李述汤； 张桥；

【Author】 Huicheng Hu;Fei Ji;Yong Xu;Jiaqi Yu;Qipeng Liu;Lei Chen;Qiao Zhang;Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University;

【机构】 苏州大学功能纳米与软物质研究院；

【摘要】 近年来,由于在光电开关、生物传感、智能材料等方面具有广泛的应用前景,可逆自组装纳米材料一直是研究热点,但目前仍然存在以下挑战:一方面,许多合成方法都使用DNA或大分子有机物作为连接物,成本高、产率低(一般仅为10%左右),而且自组装材料的性质往往会受连接物的稳定性所局限;另一方面,可控性较差,产物往往以无序的团簇形式存在,难以被精密操控。在此报告中,我们设计了一种具有双面神结构的金属-氧化硅纳米复合材料,由于氧化硅的部分包覆,金属-金属之间本不具有方向性的范德华吸引力形成了一种"受迫偶极",因此可以实现自组装。同时,通过表面修饰,可以让金属表面具有较低的表活剂密度,阻止了金属颗粒之间的进一步融合,从而实现可逆自组装。通过调节金属颗粒的空间位阻,可以选择性地制备纳米颗粒的二聚体或三聚体。我们相信这一新的方法将为纳米材料的自组装提供新的思路和方法。~[1-3]更多还原

【Abstract】 Reversible self-assembly of nanoparticles into ordered structures is essential for both fundamental and applied researches. Although extensive work has been conducted on this field, dependence on cross-linked molecules and random organization often limit their further application. Here we report a reversible and precisely controllable self-assembly of Janus metal-organosilica nanoparticles through a linker-free and fast approach by manipulating the interparticle forces, i.e., van der Waals(VDW) force, electrostatic force, and steric hindrance. By forming a Janus nanostructure, a "forced dipole" that can induce directional binding was achieved in the non-oriented VDW force. We show that dimers and trimers can be obtained by design through tuning the ratio between Au nanoparticle size and organosilica size. Moreover, this is a versatile strategy that can be applied to other metals, such as silver and palladium. After assembly, "hotspots" can be generated between adjacent nanoparticles and dramatically enhancement was observed in surface-enhanced Raman scattering. The presented reversible and linker-free self-assembly strategy opens more possibilities for by-design fabrication of new materials.更多还原