Zhang Yue-Yuan, Jia Xiang-Meng, Shi Rui, Li Shu-Jia, Zhao Huanyu, Qian Hu-Jun, Lu Zhong-Yuan
State Key Laboratory of Supramolecular Structure and Materials, International Joint Research Laboratory of Nano-Micro Architecture Chemistry, Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun, 130021, China.
Macromol Rapid Commun. 2020 Dec;41(24):e1900655. doi: 10.1002/marc.201900655. Epub 2020 Mar 5.
Polymeric single-chain nanoparticles (SCNPs) are soft nano-objects synthesized by intramolecular crosslinking of isolated single polymer chains. Syntheses of such SCNPs usually need to be performed in a dilute solution. In such a condition, the bonding probability of the two active crosslinking units at a short contour distance along the chain backbone is much higher than those which are far away from each other. Such a reaction condition often results in local spheroidization and, therefore, the formation of loosely packed structures. How to inhibit the local spheroidization and improve the compactness of SCNPs is thus a major challenge for the syntheses of SCNPs. In this study, computer simulations are performed and the fact that a precollapse of the polymer chain conformation in a cosolvent condition can largely improve the probability of the crosslinking reactions at large contour distances is demonstrated, favoring the formations of closely packed globular structures. As a result, the formed SCNPs can be more spherical and have higher compactness than those fabricated in ultradilute good solvent solution in a conventional way. It is believed this simulation work can provide a insight into the effective syntheses of SCNPs with spherical conformations and high compactness.
聚合物单链纳米颗粒（SCNPs）是通过孤立的单聚合物链的分子内交联合成的软纳米物体。此类SCNPs的合成通常需要在稀溶液中进行。在这种条件下，沿着链主链在短轮廓距离处的两个活性交联单元的键合概率远高于彼此距离较远的交联单元。这种反应条件常常导致局部球化，因此形成松散堆积的结构。因此，如何抑制局部球化并提高SCNPs的致密性是SCNPs合成中的一个主要挑战。在本研究中，进行了计算机模拟，并证明了在共溶剂条件下聚合物链构象的预塌陷可以大大提高在大轮廓距离处的交联反应概率，有利于形成紧密堆积的球状结构。结果，与以传统方式在超稀良溶剂溶液中制备的SCNPs相比，所形成的SCNPs可以更接近球形且具有更高的致密性。相信这项模拟工作可以为有效合成具有球形构象和高致密性的SCNPs提供见解。
