【作者】 李红； 唐静； 王德印； 王维；

【Author】 Hong Li;Jing Tang;Deyin Wang;Wei Wang;Center for Synthetic Soft Materials,Key Laboratory of Functional Polymer Materials of Ministry of Education and Institute of Polymer Chemistry,College of Chemistry,Nankai University;

【机构】 南开大学化学学院高分子化学研究所功能高分子材料教育部重点实验室合成软材料实验室；

【摘要】 多金属氧簇(简称POM)是一类由前过渡金属原子与氧配位桥梁而形成的具有特定结构和分子尺寸的无机阴离子簇合物。多面体寡聚笼型倍半硅氧烷(POSS)是一类具有小尺寸笼型骨架的多面体二氧化硅纳米粒子。而聚合物材料,有良好的可加工性能和力学性能,应用极为广泛。随着交叉学科的发展,无机-有机杂化领域已成为目前研究的重点。本研究中,我们选取三钒取代的Wells-Dawson型POM作为无机组分,分子式为(P2W15V3O62)9-,其外围包裹6个四丁基铵(Bu4N+)离子,该多金属氧簇与聚合度为43的聚己内酯(PCL)共价连接形成POM-PCL43杂化分子。研究发现,当温度为50度时,该杂化分子在N,N-二甲基甲酰胺(DMF)/甲醇混合溶剂体系中自组装成直径尺寸均一、长度约几百纳米的单壁纳米管,推测此时POM呈环状排列,堆积构筑成纳米管壁。进一步用高角度环形暗场像扫描透射电镜(HAADF-STEM)进行表征,可以清楚地看见单个POM沿着管的直径方向排列成一排,因此我们推测该纳米管是由10-12个POM-PCL杂化分子组成。令人惊喜的是,具有不同有机连接链的POM-POSS在该条件下同样形成结构类似的纳米管,只是直径略有不同。因此我们推测该条件下,POM之间的静电作用力驱动着POM-PCL和POM-POSS自组装成结构规整的纳米管。众所周知,生物体组装形成的结构都是非常精确的。因此我们的工作可能为更进一步探索生物体自组装之谜带来新的思路。更多还原

【Abstract】 Polyoxometalates(POMs) are a class of anionic clusters composed of early transition metals in the highest oxidation states. Organic polymers are good quality materials that have excellent processability and attractive mechanical properties. Polyhedral oligomeric polyhedral sesquiloxane(POSS) is a kind of polyhedral silica nanoparticles with small cage structure. The core of cluster we investigated is a 3 V-capped Wells-Dawson-type POM anion(P2 W15 V3 O62)9-in which three vanadium atoms on the one end are the sites for covalent organo-functionalization. This functionalized anion is covered by six tetrabutylammonium(TBA, Bu4 N+) cations. The degrees of polymerization that the poly(ε-caprolactone)s(PCL) block we used are NPCL = 43. Here we reported that the self-assembly behavior of the polyoxometalate(POM)-poly(ε-caprolactone)(PCL) hybrid in mixed solutions of N,N-Dimethylformamide(DMF)/Methanol. At 50 °C, the hybrid molecule self-organizes into single wall nanotubes with the uniform diameter and length up to hundreds of nanometers. We see bright individual POM clusters when viewed under HAADF-STEM conditions, thus we speculated that the nanotube was composed of 10-12 POM-PCL hybrid. Interestingly, using POM-POSS with different organic linkers, we also obtained similar structures with slightly different diameter. So the strong electrostatic adsorption between the POM clusters may be the main driving force of self-assembly behavior. It is well known that the self-assembly of organisms is very precise, our work may therefore lead to new ideas for further exploration of the puzzle of biological self-assembly.更多还原