DOI: 10.7302/czgw-2x26
title: Public data repository for the active loops paper published in PNAS journal.

description: Micron-scale robots require systems that can morph into arbitrary target configurations controlled by external agents such as heat, light, electricity, and chemical environment. Achieving this behavior using conventional approaches is challenging because the available materials at these scales are not programmable like their macroscopic counterparts. To overcome this challenge, we propose a design strategy to make a robotic machine that is both programmable and compatible with colloidal-scale physics. Our strategy uses motors in the form of active colloidal particles that constantly propel forward. We sequence these motors end-to-end in a closed chain forming a two-dimensional loop that folds under its mechanical constraints. We encode the target loop shape and its motion by regulating six design parameters, each scale-invariant and achievable at the colloidal scale. The research dataset includes simulation, visualization, and analysis scripts and results generated for the 2D chain loops of self-propelling particles.

File Description:;-- arrows_folding - Contains the data for the folded chain loop shapes resembling an arrowhead.;-- bending_vs_variation - Contains the data to study the stability of a particular shape in simulations as one of the segments of the shape bends and/or the distribution of propulsion on it varies.;-- curved_triangle - Contains the data to study motion and bending of a triangle shape made using chain loop.;-- example_shapes - Contains data for various examples of shapes that can be generated by designing the chain loops.;-- nskT_vs_fakT - Contains the data for a specific shape to study the effect of scaling up the number of particles (governed by ns) and the propulsion (governed by fa) in its chain.;-- stability - Contains the data and theoretical model (stability.py) to study the stability of the six different shapes.;-- tuning_design_forM - Contains the data for sequential tuning the design parameters to fold the shape "M" as described in the corresponding publication.;-- two_neighboring_cds_segments_ - Contains the data to study a system of two neighboring chain segments with respect to different parameters discussed in the publication.
description: The data contains simulation, visualization and analysis scripts, and the corresponding results produced for the publication 
Agrawal, M, Glotzer SC. (2020). Scale-free, programmable design of morphable chain loops of kilobots and colloidal motors. PNAS Journal
URL: www.pnas.org/cgi/doi/10.1073/pnas.1922635117
description: - Simulation: 2D Brownian dynamics simulations are performed using the HOOMD-blue simulation package. Simulation trajectories are in tar format that is read using the Glotzformats/Garnett software developed by the Glotzer lab at the University of Michigan.
description: - Visualization: Matplotlib is used to generate images in png format. FFMPEG is used along with the Matplotlib to generate movies in mp4 format.
description: - Analysis: Python Numpy is primarily used for writing the data analysis.
description: - Data management: Signac software, developed by the Glotzer lab, is used to generate and manage state points.
description: - Relevant File Names: run.py - simulation script for HOOMD-blue
description: visualize.py - visualization script to generate images and movies
description: dump.tar - simulation trajectory