Designing active colloidal folders

TL;DR

This paper introduces a numerical model demonstrating how active forces can be used to design and control the folding of colloidal chains into specific two-dimensional structures, with potential applications in reconfigurable materials.

Contribution

The study presents a novel model of active colloidal chains with force sequences that determine folded structures and introduces a design method for target conformations.

Findings

Active forces induce foldable structures in colloidal chains.

Sequence patterns of forces determine the resulting folded conformations.

Ensembles of mobile, compact structures can transition between conformations.

Abstract

Can active forces be exploited to drive the consistent collapse of an active polymer into a folded structure? In this paper we introduce and perform numerical simulations of a simple model of active colloidal folders, and show that a judicious inclusion of active forces into a stiff colloidal chain can generate designable and reconfigurable two dimensional folded structures. The key feature is to organize the forces perpendicular to the chain backbone according to specific patterns (sequences). We characterize the physical properties of this model and perform, using a number of numerical techniques, an in-depth statistical analysis of structure and dynamics of the emerging conformations. We discovered a number of interesting features, including the existence of a direct correspondence between the sequence of the active forces and the structure of folded conformations, and we discover the existence of an ensemble of highly mobile compact structures capable of moving from conformation to conformation. Finally, akin to protein design problems, we discuss a method that is capable of designing specific target folds by sampling over sequences of active forces.