Multiblock copolymers exhibiting spatio-temporal structure with autonomous viscosity oscillation

Abstract

Here we report an ABA triblock copolymer that can express microscopic autonomous formation and break-up of aggregates under constant condition to generate macroscopic viscoelastic self-oscillation of the solution. The ABA triblock copolymer is designed to have hydrophilic B segment and self-oscillating A segment at the both sides by RAFT copolymerization. In the A segment, a metal catalyst of chemical oscillatory reaction, i.e., the Belousov-Zhabotinsky (BZ) reaction, is introduced as a chemomechanical transducer to change the aggregation state of the polymer depending on the redox states. Time-resolved DLS measurements of the ABA triblock copolymer confirm the presence of a transitional network structure of micelle aggregations in the reduced state and a unimer structure in the oxidized state. This autonomous oscillation of a well-designed triblock copolymer enables dynamic biomimetic softmaterials with spatio-temporal structure.

Amoeba-like self-oscillating polymeric fluids with autonomous sol-gel transition

“…Interestingly, in the case of these ABC triblock copolymers, sequential aggregation was observed in the reduced state, that is, the oscillating profile showed sharp top peaks. In contrast, in a previous study using the ABA triblock copolymer, a plateau region appeared in the oscillating profiles in the reduced state9. Therefore, we conclude that due to the stepwise aggregation process, the micelle structures of the ABC triblock copolymer synthesized in this study must have fewer loop chains than those of the ABA triblock copolymer.…”

“…Remarkably, as seen in Fig. 3b, when the polymer concentration was 5.0 wt%, the viscosity amplitude reached a maximum of 1,960 mPa s. This value is comparable to the amplitude occurring in living amoeba, and about 10 3 times larger than those observed in previous reports789. Supplementary Fig.…”

“…Further, a self-oscillating polymer brush surface was prepared as artificial cilia implementing autonomous nanoactuation6. Moreover, autonomous viscosity oscillations of a fluid were realized by utilizing microgels7, a metallo-supramolecular complex8 or block copolymer solutions 9. In addition, self-oscillation between unimer/micelle10 or unimer/vesicle (polymersome)1112 structures was also achieved by utilizing synthetic block copolymers78.…”

“…9). In contrast, here, we have succeeded in increasing this amplitude to 2,000 mPa s, which is equal to the oscillation amplitude in living amoeba.…”

Evolved Colloidosomes Undergoing Cell‐like Autonomous Shape Oscillations with Buckling

“…[7,8] To realize autonomous oscillatory behaviors that exist in living systems by using synthetic materials,w eh ave developed "self-oscillating" gels which exhibit autonomous periodic swelling/deswelling changes driven by an oscillatory chemical reaction. [13][14][15][16][17] In addition to our studies,o ther groups have also reported self-oscillating polymer materials. [13][14][15][16][17] In addition to our studies,o ther groups have also reported self-oscillating polymer materials.…”