Speaker
Description
Simulations by Sherman et al. (2016) [1] demonstrated that time-dependent, periodically toggled interparticle attractions in nanoparticles can anneal disorder, enable escape from kinetically arrested states, and promote the formation of well-ordered crystalline domains. In our work, we investigate a similar out-of-equilibrium pathway to structure formation in a density- and refractive-index-matched PMMA colloidal dispersion (1.3um in diameter). This is done by applying a toggled external AC electric field that alternates between on and off states, thereby driving the system between regimes of steady depletion interactions and induced dipolar interactions. Using the dipolar–depletion phase diagram as a reference (Semwal et al., 2022 [2] ), we explore how toggling parameters (field amplitude, on-time, and off-time), depletion strength, and colloid volume fraction—affects the kinetics and emergent phases of the system. Structural ordering is quantified using the pair correlation function, bond-orientational order parameters, and the non-affine displacement parameter, characterizing the microstructure.
[1] Zachary M. Sherman and James W. Swan. Dynamic, directed self-assembly of nanoparticles via toggled interactions. ACS nano, 10(5):5260–5271, 2016.
[2] Shivani Semwal, Cassandra Clowe-Coish, Ivan Saika-Voivod, and Anand Yethiraj. Tunable colloids with dipolar and depletion interactions: towards field switchable crystals and gels. Phys. Rev. X, 12(17):041021, 2022.
| Keyword-1 | Colloidal self-assembly |
|---|---|
| Keyword-2 | Structure formation kinetics |
| Keyword-3 | Nonequilibrium colloids |