双刚性杂化分子的溶液自组装研究

Solution self-assembly studies of bi-rigid hybrid molecules

为了了解以非共价键结合的双刚性杂化分子在不同溶剂体系下的溶液自组装,本文利用氨丙基七异丁基多面体低聚硅氧烷(Si_(8)O_(12)NC_(31)H_(71),简称BPOSS-NH_(2))与亲水性硅酸钨(H_(4)SiW_(12)O_(40),简称HSiW)发生氨基质子化反应,形成双亲性杂化分子。通过核磁光谱、红外光谱、元素分析确定了杂化分子的成分。通过透射电子显微镜、扫描电子显微镜对溶液中自组装的纳米结构进行了表征。研究发现,质子化得到的杂化分子在丙酮-水体系中能够组装成层状的规则二维纳米片。当溶剂体系改为四氢呋喃-水时,杂化分子能够组装得到三维囊泡。在丙酮-水体系中,在组装过程中随着水的加入,杂化分子中的BPOSS-NH2的溶解度变小,导致该双亲性杂化分子缺乏分子运动性,所以最终组装体为层状规则二维纳米片。在四氢呋喃-水体系中,尽管组装过程中有水的加入,由于BPOSS-NH_(2)在四氢呋喃中的溶解度较高,所以杂化分子中的BPOSS-NH_(2)具有一定的分子运动性,因而在自组装初期形成的双层结构具有一定的柔性,可以形成二维曲面,最终得到空心囊泡结构。

In order to understand the solution self-assembly of doubly rigid hybrid molecules bound by non-covalent bonds in different solvent systems.In this paper,Aminopropyl heptaisobutyl polyhedral oligomeric siloxanes(Si_(8)O_(12)NC_(31)H_(71),abbreviated as BPOSS-NH_(2))were used to form amphiphilic hybrid molecules by amino-protonation reaction with hydrophilic tungsten silicate(H_(4)SiW_(12)O_(40),denoted as HSiW).The composition of the hybridized molecules was determined by nuclear magnetic spectroscopy,infrared spectroscopy and elemental analysis.The self-assembled nanostructures in solution were characterized by transmission electron microscopy and scanning electron microscopy.It was found that the hybridized molecules obtained by protonation were able to assemble into layered regular two-dimensional nanosheets in the acetone-water system.When the solvent system was changed to tetrahydrofuran-water,the hybrid molecules were able to assemble to obtain three-dimensional vesicles.In the acetone-water system,with the addition of water during the assembly process,the solubility of BPOSS-NH_(2) in the hybrid molecule becomes smaller,resulting in the lack of molecular motility of this amphiphilic hybrid molecule,so the final assembly is a lamellar regular two-dimensional nanosheet.In the tetrahydrofuran-water system,despite the addition of water in the assembly process,the BPOSS-NH_(2) in the hybrid molecule has certain molecular motility due to the higher solubility of BPOSS-NH_(2) in tetrahydrofuran,thus the bilayer structure formed at the early stage of self-assembly had certain flexibility and lould form a two-dimensional surface,and finally a hollow vesicle structure was obtained.