Fabrication of Micropatterned Self‐Oscillating Polymer Brush for Direction Control of Chemical Waves

Abstract

The propagation control of chemical waves via a pentagonal patterned structure in a self-oscillating polymer brush composed of N-isopropylacrylamide and a metal catalyst for the Belousov-Zhabotinsky (BZ) reaction is reported. The patterned self-oscillating polymer brush is prepared by combining surface-initiated atom transfer radical polymerization and maskless photolithography. Surface modification is confirmed by X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, 3D measuring laser microscopy, and fluorescence microscopy. The polymer brush patterns are fabricated with gaps between the pentagonal regions, and investigations on the effect of the gap distance on the BZ reaction reveal that at the appropriate distance, chemical waves propagate across the array from the plane to the corner between the patterns. Unidirectional control is achieved not only in the 1D array, but also in a 2D curved array. This patterned self-oscillating polymer brush is a novel and advantageous approach for creating an autonomous dynamic soft interface.

Oscillating Reactions Meet Polymers at Interfaces

“…In view of potential applications of self-oscillating polymer brushes, controlling the direction of the propagating chemical wave is an important factor. Homma et al [89] applied patterning as an alternative method to induce controlled nanoactuation in a self-oscillating polymer brush, to increase the control over the direction of the oscillation (Figure 8). It is known from the seminal work of Agladze et al [90] that patterning of reactive and non-reactive areas with appropriate shapes can be an effective way to control the propagation of chemical waves.…”

The increasing dynamic, functional complexity of bio-interface materials

“…in the order of 0.5 Hz) 58 to achieving autonomously self-propelled motion, 59 autonomous transport, 57 and unidirectional control of self-oscillating waves. 60 The emphasis thus far has been on modifications of the internal structure of the BZ gels that are expected, together with hierarchical integration, to continue to drive the next level of complexity and function, such as time-asymmetrical responses or capability to adapt to external signals. However, if these out-of-equilibrium systems are to progress from proof-of-concept to biomedical technological solutions, the feedback-controlled systems will need to be designed to be biocompatible, sustain long lasting stability and operation in biological environments and utilise substrates at biologically relevant concentrations.…”

Self-oscillating polymer gels as biomimetic and smart softmaterials

“…Further, there have been new developments toward autonomous polymer actuating systems with micro or nano-order scale such as polymer solution [49][50][51][52][53][54][55][56][57], polymer brush [58][59][60][61], polymer micelles [62][63][64], polymer vesicles [65][66][67][68], colloidsomes [69]. Especially, amoeba-like intermittent autonomous moving motion accompanying sol-gel oscillation under constant condition was achieved by strategically designed synthetic polymers [70,71].…”

“…Self-oscillating polymer brushes have been prepared by grafting self-oscillating polymers onto a glass substrate using the SI-ATRP method (Fig. 3) [58][59][60][61]. Chemical wave propagation was clearly observed on the surface.…”