Molecular Studies of Phase Transitions in Soft Matter: The Lower Critical Solution Temperature Transition Études moléculaires de transitions de phases dans la matière molle: LCST

在这个为期5年的研究计划中，我们希望利用强大的多尺度方法来研究一个具有重大科学和技术意义的主题：温敏聚合物的低临界溶解温度（LCST）。高于LCST，温敏聚合物在水溶液中的溶解度降低，导致相分离。由于其特殊的技术和生物医学利益，这种现象在过去二十年中受到越来越多的关注。尽管有大量的研究，许多基本的问题仍然没有完全理解，如从线圈到球（CTG）的转变，聚集体的形成和它们的稳定性，共聚单体和共溶效应。从概念上讲，相变是一种集体现象。通过精确描述原子相互作用和分子排列来评估协同长度，将使相变的描述变得无价，并允许揭示分子变化。相变的热力学或平均场模型所固有的普适性必须被看作是一种极限。因此，拟议的研究计划旨在通过利用多尺度方法来解决这些重要且基本的问题。

In this 5-year research program, we want to exploit the powerful multi-scale approach to study a topic of great scientific and technological interest: Lower Critical Solution Temperature (LCST) in thermoresponsive polymers. Above the LCST, thermoresponsive polymers in aqueous solution show a decrease in their solubility, resulting in phase separation. Due to its particular technological and biomedical interests, such phenomenon has been increasingly scrutinized over the past two decades. Despite numerous studies, many fundamental questions remain not fully understood such as the transition from coil-to-globule (CTG), the aggregate formation and their stability, the co-monomer and the cononsolvency effects. Conceptually, a phase transition is a collective phenomenon. Evaluating a cooperativity length, through an accurate depiction of atomic interactions, and a fortiori molecular arrangement, will make the description of phase transition invaluable, and allow unveiling molecular changes. The universal character, inherent to thermodynamics, or to the mean-field model, of a phase transition must be considered as a limit. The proposed research program is thus aimed at addressing such important and fundamental questions by exploiting the multi-scale approach.