On-surface polymerization is a promising technique to prepare organic functional nanomaterials that are challenging to synthesize in solution, but it is typically used on metal substrates, which play a catalytic role. Previous examples on insulating surfaces have involved intermediate self-assembled structures, which face high barriers to diffusion, or annealing to higher temperatures, which generally causes rapid dewetting and desorption of the monomers. Here we report the photoinitiated radical polymerization, initiated from a two-dimensional gas phase, of a dimaleimide monomer on an insulating KCl surface. Polymer fibres up to 1 μm long are formed through chain-like rather than step-like growth. Interactions between potassium cations and the dimaleimide’s oxygen atoms facilitate the propagation of the polymer fibres along a preferred axis of the substrate over long distances. Density functional theory calculations, non-contact atomic force microscopy imaging and manipulations at room temperature were used to explore the initiation and propagation processes, as well as the structure and stability of the resulting one-dimensional polymer fibres.

表面聚合是制备在溶液中难以合成的有机功能纳米材料的有前途的技术，但它通常用于具有催化作用的金属基材上。绝缘表面上的先前示例涉及中间的自组装结构，该结构面对扩散的高障碍，或面对较高温度的退火，这通常会引起单体的快速脱湿和解吸。在这里，我们报告了在绝缘的KCl表面上，由二维气相引发的二马来酰亚胺单体的光引发的自由基聚合。通过链状而不是阶梯状生长形成长达1μm长的聚合物纤维。钾阳离子和二马来酰亚胺的氧原子之间的相互作用促进了聚合物纤维沿基材的优选轴长距离传播。密度泛函理论计算，非接触原子力显微镜成像和在室温下的操作被用来探讨引发和传播过程，以及所得一维聚合物纤维的结构和稳定性。