Ren Liangxuan, Lu Xueting, Yan Jiatao, Zhang Afang, Li Wen
International Joint Laboratory of Biomimetic and Smart Polymers, School of Materials Science and Engineering, Shanghai University, Mailbox 152, 99 Shangda Road, Shanghai 200444, China.
J Colloid Interface Sci. 2025 Jan;677(Pt A):928-940. doi: 10.1016/j.jcis.2024.08.001. Epub 2024 Aug 5.
Supramolecular assembly of helical homopolymers to form stable chiral entities in water is highly valuable for creating chiral nanostructures and fabricating chiral biomaterials. Here we report on thermally induced supramolecular assembly of helical dendronized poly(phenylacetylene)s (PPAs) in aqueous solutions, and their in-situ photo-crosslinking at elevated temperatures to afford crosslinked nano-assemblies with hierarchical structures and stabilized helicities. These helical dendronized homopolymers carry cinnamate-cored dendritic oligoethylene glycol (OEG) pendants, which exhibit characteristic thermoresponsive behavior. Their thermal aggregation confers hexagonal packing of the polymer chains, and simultaneously resulting in enhancement of their chiralities. Assisted by radial amphiphilicity and worm-like molecular geometry, these dendronized PPAs form supramolecular twisted fibers, spheroid particles or toroids via thermal aggregation. Through UV photoirradiation above their cloud points (Ts), cycloaddition of cinnamate moieties from the dendritic pendants promotes intermolecular crosslinking of dendronized PPA chains within the thermal aggregates, and simultaneously, the dynamic morphologies and supramolecular chirality from the dendronized PPAs through thermally induced aggregation can be fixed. In addition, photo-crosslinking can be occurred solely within individual aggregates due to the protection of densely packed dendritic OEGs. Therefore, various crosslinked assemblies from the dendronized homopolymers with tailorable morphologies and stabilized chirality are fabricated by tuning their thermally induced dynamic aggregations followed by in-situ photo-crosslinking. We believe that this work paves a convenient route to fabricate chiral assemblies with stabilized morphologies and fixed chiralities from dynamic helical homopolymers through intermolecular crosslinking, which can be promising for various chiral applications.
螺旋状均聚物在水中形成稳定手性实体的超分子组装对于创建手性纳米结构和制造手性生物材料具有极高价值。在此，我们报道了螺旋状树枝状聚（苯乙炔）（PPA）在水溶液中的热诱导超分子组装，以及它们在高温下的原位光交联，以获得具有层次结构和稳定螺旋度的交联纳米组装体。这些螺旋状树枝状均聚物带有肉桂酸酯核的树枝状低聚乙二醇（OEG）侧链，表现出独特的热响应行为。它们的热聚集赋予聚合物链六边形堆积，同时增强其手性。在径向两亲性和蠕虫状分子几何形状的辅助下，这些树枝状PPA通过热聚集形成超分子扭曲纤维、球状颗粒或环面。通过在其浊点（Ts）以上进行紫外光照射，树枝状侧链中肉桂酸酯部分的环加成促进了热聚集体内树枝状PPA链的分子间交联，同时，树枝状PPA通过热诱导聚集产生的动态形态和超分子手性可以被固定。此外，由于密集堆积的树枝状OEG的保护，光交联可以仅在单个聚集体内发生。因此，通过调节其热诱导动态聚集然后进行原位光交联，制备了具有可定制形态和稳定手性的各种树枝状均聚物交联组装体。我们相信这项工作为通过分子间交联从动态螺旋状均聚物制备具有稳定形态和固定手性的手性组装体开辟了一条便捷途径，这对于各种手性应用可能具有广阔前景。
