Bistable self-assembly in homogeneous colloidal systems for flexible modular architectures.

G Steinbach,E V Novak,S S Kantorovich,S Gemming,D Nissen,M Albrecht,A Erbe,P A Sánchez

doi:10.1039/c5sm02899j

Abstract

This paper presents a homogeneous system of magnetic colloidal particles that self-assembles via two structural patterns of different symmetry. Based on a qualitative comparison between a real magnetic particles system, analytical calculations and molecular dynamics simulations, it is shown that bistability can be achieved by a proper tailoring of an anisotropic magnetization distribution inside the particles. The presented bistability opens new possibilities to form two-dimensionally extended and flexible structures where the connectivity between the particles can be changed in vivo.

Highlights

Colloidal self-assembly is widely used to systematically study building principles of structures of various complexities
Flexibility/variability of this system stems from the fact that there coexist two almost equiprobable self-assembly scenarios. We show that these scenarios can be realized by magnetic particles with a permanent, anisotropic magnetization distribution, as the latter leads to essential deviations from the interaction landscape of particles that can be approximated by a single point dipole
Analytically and by molecular dynamics simulations, that the proposed model reproduces both stable configurations observed in the experimental system

Summary

Introduction

Colloidal self-assembly is widely used to systematically study building principles of structures of various complexities. One especially interesting example for complex structures is given by modular architectures They are prevalent in natural materials on the microscale[1,2] and occur in numerous biological systems.[3] Commonly, such structures form by self-assembly of modular units into larger structures, for example tissues,[4,5] leading to complex designs with variable functionalities. The longstanding quest for the replication[6] of such structures, based on self-assembly of artificially fabricated constituents, is impeded by the difficulty to imitate those naturally occurring structural processes. This can be tackled by developing artificial, selforganizing systems that provide large flexibility in their design. For a controlled artificial self-assembly it is important to formulate basic, simple building principles and to prove that the latter can determine the formation of complex and flexible structures

Methods

Results

Conclusion