Institute for Macromolecular Chemistry, University of Freiburg, Stefan-Meier-Str. 31, 79104, Freiburg, Germany.
Freiburg Materials Research Center (FMF), University of Freiburg, Stefan-Meier-Str. 21, 79104, Freiburg, Germany.
Angew Chem Int Ed Engl. 2021 Mar 22;60(13):7117-7125. doi: 10.1002/anie.202014417. Epub 2021 Feb 24.
Microgels are soft colloids that show responsive behavior and are easy to functionalize for applications. They are considered key components for future smart colloidal material systems. However, so far microgel systems have almost exclusively been studied in classical responsive switching settings using external triggers, while internally organized, autonomous control mechanisms as found in supramolecular chemistry and DNA nanotechnology relying on fuel-driven out-of-equilibrium concepts have not been implemented into microgel systems. Here, we introduce chemically fueled transient volume phase transitions (VPTs) for poly(methacrylic acid) (PMAA) microgels, where the collapsed hydrophobic state can be programmed using the fuel concentration in a cyclic reaction network. We discuss details of the system behavior as a function of pH and fuel amount, unravel kinetically trapped regions and showcase transient encapsulation and time-programmed release as a first application.
微凝胶是具有响应行为的软胶体，易于功能化，可用于各种应用。它们被认为是未来智能胶体材料系统的关键组成部分。然而，到目前为止，微凝胶系统几乎仅在使用外部触发的经典响应切换设置中进行研究，而在超分子化学和 DNA 纳米技术中发现的内部组织、自主控制机制则依赖于燃料驱动的非平衡概念，尚未应用于微凝胶系统中。在这里，我们为聚（甲基丙烯酸）（PMAA）微凝胶引入了化学燃料瞬态体积相转变（VPT），其中使用循环反应网络中的燃料浓度可以对疏水性塌陷状态进行编程。我们讨论了作为 pH 和燃料量函数的系统行为的细节，揭示了动力学捕获区域，并展示了作为第一个应用的瞬态封装和时间编程释放。
