Chemically Fueled Volume Phase Transition of Polyacid Microgels

Abstract

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.

Autonomous DNA nanostructures instructed by hierarchically concatenated chemical reaction networks

“…Taking the inspiration from nature, efforts have been made to develop synthetic fuel-driven non-equilibrium systems ranging from molecular to macroscopic levels 5 , 7 – 9 . Over the last few years, chemical fuels and CRNs have been implemented to fuel supramolecular self-assemblies for various transient systems such as for conformational switches 10 , supramolecular fibrils 11 – 13 , colloid self-assembly 14 – 16 , hydrogel materials 13 , 17 – 21 , and photonic devices 22 . Despite progress, the development of artificial non-equilibrium systems showing high structural precision and at the same time incorporating system complexities, such as multicomponent assembly strategies or connection of more than one CRN, remains a challenge.…”

Chemically Fueled Block Copolymer Self‐Assembly into Transient Nanoreactors**

“…Furthermore, we tested the formation of hydrophobic domains by a Nile Red fluorescence assay. This assay is a convenient method to test whether hydrophobic molecules can be incorporated into assemblies (Figure 2E) [28] . Such inclusion of hydrophobic derivatives would be a requirement for the use of our transient assemblies as nanoreactors.…”

Temporally programmed polymer - solvent interactions using a chemical reaction network

“…A second reaction subsequently converts the intermediate to its inactive precursor state by spontaneously forming a waste product (deactivation). 14 Autonomously dynamic materials made using fuel-driven out-of-equilibrium CRNs include microgels 15 , supramolecular gels 11 , nanoparticles 16 and vesicles 17 . These materials use a wide variety of material activation processes including different chemical fuels, light or ultrasound to name a few.…”

“…These materials use a wide variety of material activation processes including different chemical fuels, light or ultrasound to name a few. [18][19][20] In contrast, the deactivation mechanism in chemically fuelled non-equilibrium CRNs relies frequently on hydrolysis 9,15,16,[21][22][23] or internal pH change [10][11][12][13] and only a few non-enzymatic alternatives have been investigated [24][25][26] . Regulation of the deactivation reaction in CRNs remains a key issue in out-of-equilibrium systems.…”