Molecular Design for Micrometer-Scale Self-Assembly of Amphiphilic dendrimer

二肽核聚（苄基醚）树状大分子tert-Boc-Tyr(Ln)-Ala （Ln = n层状枝状楔）（n = 3,4）在几种有机溶剂中形成物理凝胶。凝胶在树突楔的吸收带上显示出强的CD带，此外由于二肽核的作用，CD带也增强了。红外光谱和DSC分析表明，凝胶化是通过二肽核的氢键相互作用发生的，可能是由树突楔间的范德华力稳定的。扫描电镜分析表明，干燥凝胶含有微米级纤维，这些纤维是由许多直径约为20 nm的初级原纤维束组成的。与此成果相关，我们还发现，在pH 6.3的磷酸盐缓冲溶液中，具有外羧酸表面的两亲性聚苯醚树状大分子形成直径为250nm的均匀胶束。这两项发现为纳米级超结构枝晶材料的设计提供了一种新的策略。

Dipeptide-core poly (benzyl ether) dendrimers, tert-Boc-Tyr(Ln)-Ala (Ln = n-layered dendritic wedge) (n = 3, 4), formed a physical gel in several organic solvents. The gel displayed strong CD bands at the absorption bands of the dendritic wedge, in addition to an enhanced CD band due to the dipeptide core. Infrared spectroscopy and DSC analysis indicated that the gelation occurs via hydrogen-bonding interactions of the dipeptide core, which are possibly stabilized by van der Waals forces among the dendritic wedges. SEM analysis showed that the dried gel contains micrometer-scale fibers, which are bundles of numerous elementary fibrils with a diameter of approximately 20 nm. In relation to this achievement, we also found that an amphiphilic poly (benzyl ether) dendrimer with an exterior carboxylic acid surface forms a uniform micelle with a diameter of 250nm in phosphate buffer solution at pH 6.3. These two findings provide a new strategy for the design of micrometer-scale superstructured dendritic materials with nanometric precision.