A phase-field model for solutions of DNA-made particles

We present a phase-field model based on the Cahn-Hilliard equation to investigate the properties of phase separation in DNA nanostar systems. Leveraging a realistic free-energy functional derived from Wertheim theory, our model captures the thermodynamic properties of self-assembling DNA nanostars under various conditions. This approach allows for the study of both one-component and multi-component systems, including mixtures of different nanostar species and cross-linkers. Through numerical simulations, we demonstrate the model ability to replicate experimental observations, including liquid-liquid phase separation, surface tension variation, and the structural organisation of multi-component systems. Our results highlight the versatility and predictive power of the Cahn-Hilliard framework, particularly for complex systems where detailed simulations are computationally prohibitive. This work provides a robust foundation for studying DNA-based materials and their potential applications in nanotechnology and biophysics, including liquid-liquid phase separation in cellular environments.