AI 中文总结
本研究探究脂质包被琼脂糖微凝胶中PEG的结晶路径，发现膜限域与凝胶化协同改变PEG局部水合环境，稳定类非晶态前驱体并调控结晶路径，确定二者耦合是调控受限软材料中PEG结晶的关键因素。
AI 中文摘要
脂质包被的微米级水凝胶提供了受限的水合环境，其中聚合物的相行为可能与本体环境显著不同。本研究考察了封装在脂质包被琼脂糖微凝胶中的聚乙二醇（PEG）的结晶路径。令人惊讶的是，偏光显微镜显示，在相应本体溶液中PEG仍保持非晶态的条件下，微凝胶内出现双折射现象；该双折射在加热时消失，进一步冷却或局部机械刺激后会自发重现。红外显微光谱表明，双折射微凝胶含有结晶PEG，而非双折射微凝胶中的PEG则呈类非晶态，这说明结晶前存在亚稳态前驱体。此外，冷却至相分离温度以下会在膜附近优先形成富PEG区域，提示膜润湿作用决定了结晶前PEG的空间分布。综上，这些结果表明膜限域与琼脂糖凝胶化协同改变了PEG的局部水合环境，从而稳定了类非晶态前驱体并调控了后续结晶路径。本研究的发现确定了膜润湿与凝胶化的耦合是调控受限软材料中PEG结晶的关键因素。
英文摘要
Lipid-coated microscale hydrogels provide confined, hydrated environments in which polymer phase behavior can differ markedly from that in bulk. Here, we investigate the crystallization pathway of poly(ethylene glycol) (PEG) encapsulated in lipid-coated agarose microgels. Surprisingly, polarized-light microscopy reveals birefringence in the microgels under conditions where PEG remains non-crystalline in the corresponding bulk solution. The birefringence disappears upon heating and spontaneously reappears after further cooling or upon local mechanical stimulation. Infrared microspectroscopy demonstrates that the birefringent microgels contain crystalline PEG, whereas non-birefringent microgels contain PEG in an amorphous-like state, indicating the existence of a metastable precursor prior to crystallization. Furthermore, cooling below the phase-separation temperature produces PEG-rich domains preferentially near the membrane, suggesting that membrane wetting governs the spatial distribution of PEG before crystallization. Together, these results indicate that membrane confinement and agarose gelation cooperatively alter the local hydration environment of PEG, thereby stabilizing an amorphous-like precursor and redirecting the subsequent crystallization pathway. Our findings identify the coupling of membrane wetting and gelation as a key factor governing PEG crystallization in confined soft materials.
Comments8 pages, 6 figures
