Polymers capable of undergoing rapid degradation after exposure to light irradiation hold great promise in a plethora of applications including biomedical materials, smart coatings and hydrogels, degradable plastics, and others. Herein, the synthesis of new light-degradable polyacylhydrazones comprising alternating hydrophilic poly(ethylene glycol) (PEG) segments and hydrophobic aromatic units, are presented. A polycondensation reaction between diacylhydrazide terminated poly(ethylene glycols) ( = 4000 and 1500 g mol) with aromatic dicarbonyl comonomers was employed for the synthesis of the amphiphilic polyacylhydrazones. By increasing the number of aromatic moieties in close proximity to the acylhydrazone bonds and varying the type, dialdehyde diketone, and the conjugation length of the hydrophobic comonomers, the absorption maximum of the copolymers was shifted to longer wavelengths. The amphiphilic polyacylhydazones derived from the PEG with = 4000 g mol self-assembled in water into spherical nanoparticles, evidenced by SEM and DLS. Finally, light irradiation of the polymer assemblies induced the photocleavage of the acylhydrazone bonds along the polymer backbone, which led to the dissociation of the polymer nanoparticles and the formation of a PEG derivative as the main photoproduct.

中文翻译：

---

主链光裂解聚酰腙的合成、自组装和表征

受到光照射后能够快速降解的聚合物在生物医学材料、智能涂料和水凝胶、可降解塑料等众多应用中具有广阔的前景。在此，提出了包含交替的亲水性聚乙二醇（PEG）片段和疏水性芳香族单元的新型光可降解聚酰腙的合成。采用二酰肼封端的聚乙二醇（= 4000 和 1500 g mol）与芳香族二羰基共聚单体之间的缩聚反应来合成两亲性聚酰腙。通过增加紧邻酰腙键的芳香族部分的数量并改变疏水性共聚单体的类型、二醛二酮和共轭长度，共聚物的最大吸收移动到更长的波长。 SEM 和 DLS 证明，源自 PEG 的两亲性聚酰腙在水中自组装成球形纳米粒子，摩尔质量 = 4000 g。最后，聚合物组装体的光照射引起沿聚合物主链的酰腙键的光裂解，导致聚合物纳米颗粒解离并形成作为主要光产物的PEG衍生物。