Molecular bottlebrushes (MBBs) with a hydrophobic core and a hydrophilic shell may exist as well-defined unimolecular nanoparticles in water. However, they may also aggregate to form large particles if the structure of the hydrophilic and hydrophobic segments fail to be rationally controlled. Herein, a series of core-shell amphiphilic MBBs with a poly (ε-caprolactone) (PCL) backbone bearing two block copolymer side chains, poly (butyl acrylate)-b-poly ((oligo (ethylene glycol) acrylate) (PBA-b-POEGA) and poly (butyl acrylate)-b-poly (ethylene glycol) (PBA-b-PEG), were synthesized through grafting-from and grafting-onto strategies. Their hydrophilic shells are different in topology: POEGA is comblike whereas PEG is linear. The stability of the two kinds of MBB with the similar composition as unimolecular nanoparticles in water and their encapsulation capacity for guest-molecule were evaluated. Compared to the MBB with a linear PEG shell, those with comblike POEGA side chains remained stable against aggregation as demonstrated by atomic force microscopy and dynamic light scattering measurement. The MBB with a POEGA shell also displayed a much higher encapsulating capacity to a model guest molecule, pyrene, by hydrophobic interaction. This study provides guidance to the rational preparation of MBBs for applications as molecular vehicles.

具有疏水核和亲水壳的分子刷（MBB）可能以明确定义的单分子纳米粒子存在于水中。但是，如果不能合理地控制亲水和疏水链段的结构，它们也可能聚集形成大颗粒。本文中，一系列具有两个嵌段共聚物侧链的聚（ε-己内酯）（PCL）主链的核-壳两亲MBB ，聚（丙烯酸丁酯）-b-聚（（低聚（乙二醇）丙烯酸酯）（PBA- b -POEGA）和聚（丙烯酸丁酯）-b-聚乙二醇（PBA- b-PEG）是通过嫁接策略和嫁接策略合成的。它们的亲水壳的拓扑结构不同：POEGA是梳状的，而PEG是线性的。评估了两种与单分子纳米粒子组成相似的MBB在水中的稳定性及其对客体分子的包封能力。与具有线性PEG壳的MBB相比，具有梳状POEGA侧链的MBB保持稳定，可防止聚集，如原子力显微镜和动态光散射测量所证明的那样。通过疏水相互作用，带有POEGA壳的MBB还表现出对模型客体分子pyr更高的封装能力。这项研究为合理制备MBB用作分子载体提供了指导。