Direct observation of phase transitions in truncated tetrahedral microparticles under quasi-2D confinement

Colloidal crystals are used to understand fundamentals of atomic rearrangements in condensed matter and build complex metamaterials with unique functionalities. Simulations predict a multitude of self-assembled crystal structures from anisotropic colloids, but these shapes have been challenging to fabricate. Here, we use two-photon lithography to fabricate Archimedean truncated tetrahedrons and self-assemble them under quasi-2D confinement. These particles self-assemble into a hexagonal phase under an in-plane gravitational potential. Under additional gravitational potential, the hexagonal phase transitions into a quasi-diamond two-unit basis. In-situ imaging reveal this phase transition is initiated by an out-of-plane rotation of a particle at a crystalline defect and causes a chain reaction of neighboring particle rotations. Our results provide a framework of studying different structures from hard-particle self-assembly and demonstrates the ability to use confinement to induce unusua..., , , # Direct observation of phase transitions in truncated tetrahedral microparticles under quasi-2D confinement

This dataset contains the images, .csv files, and code needed to reproduce the results to support the conclusion of the manuscript.

### Files and Folders

The file structure is ordered relative to the dataset collected for each main figure in the manuscript, as well as some of the supplemental information data. Each folder can contain images (.png, .tif), .csv files, and Jupyter notebooks (.ipynb) that will help reproduce the dataset in the main manuscript. Each folder that has code has a `README.md` that helps facilitate installing and running the code.

#### **/Figure 1**

* *README.md*

* Markdown (.md) file that has details for installing a conda python environment to run the necessary analysis code for the data in Figure 1.
* *environment.yml*

* YAML (.yml) file that declares all necessary python libraries to run the analysis code (*orderParams.py and Or...