Makromolekulare Chemie II, Universität Bayreuth, D-95440 Bayreuth, Germany.
J Am Chem Soc. 2012 Aug 22;134(33):13850-60. doi: 10.1021/ja305903u. Epub 2012 Aug 13.
We present a novel, versatile, and simple solution-based routine to produce soft, nanosized Janus particles with tunable structural and physical properties at high volume yield. This process is based on the cross-linking of compartments within precisely defined multicompartment micelles (MCMs), which are themselves formed by the self-assembly of ABC triblock terpolymers. Therein, the C blocks form the stabilizing corona emanating from B compartments, which in turn reside on an A core. Cross-linking of the B compartments allows to permanently fixate the phase-separated state and dissolution in a good solvent for all blocks breaks up the MCMs into single Janus particles. They now consist of a core of cross-linked B blocks and two phase-separated hemispheres of A and C. The process gives access to unprecedented structural features such as tunable core diameter and control over the Janus balance ranging from dominant A side to equal hemispheres to dominant C side. We demonstrate that this simple one-pot approach can be extended to a range of triblock terpolymers with different block lengths and block chemistries to furnish a library of tailor-made Janus particles with widely tunable physical properties. Such a diversity and simplicity has remained unreachable with our previously developed approach using the controlled cross-linking of bulk morphologies. We show that this new synthetic route can be upscaled to a high volume yield of 10 wt %, thereby enabling large-scale applications. We further demonstrate the effect of the Janus balance on colloidal self-assembly. Janus particles with a dominant hydrophobic and a small hydrophilic patch aggregate into large clusters in water, but merely di- or trimerize in chloroform.
我们提出了一种新颖、多功能且简单的基于溶液的方案，可在高体积产率下生产具有可调结构和物理性质的软纳微级别的 Janus 粒子。该方法基于在精确限定的多隔室胶束（MCM）内交联隔室，而 MCM 本身是由 ABC 三嵌段共聚物自组装形成的。其中，C 块形成从 B 隔室发出的稳定冠，而 B 隔室又位于 A 核上。B 隔室的交联可永久固定相分离状态，所有嵌段的良溶剂溶解会将 MCM 分解成单个 Janus 粒子。此时，它们由交联的 B 块核和两个相分离的 A 和 C 半球组成。该过程可获得前所未有的结构特征，如可调核直径和对 Janus 平衡的控制，范围从主导 A 侧到相等的半球到主导 C 侧。我们证明，这种简单的一锅法可以扩展到一系列具有不同嵌段长度和嵌段化学性质的三嵌段共聚物，以提供具有广泛可调物理性质的定制 Janus 粒子库。这种多样性和简单性是我们以前使用体形态的受控交联开发的方法无法实现的。我们证明，这种新的合成路线可以大规模放大到 10wt%的高体积产率，从而实现大规模应用。我们进一步展示了 Janus 平衡对胶体自组装的影响。具有主导疏水性和小亲水性斑块的 Janus 粒子在水中聚集成长大的团簇，但在氯仿中仅二聚或三聚。
