Directing liquid crystalline self-organization of rod-like particles through tunable attractive single tips

Andrii Repula (1) , Mariana Oshima Menegon (2) , Cheng Wu (1) , Paul van Der Schoot (3) , Eric Grelet (1)

1 CRPP - Centre de Recherche Paul Pascal
2 MacDiarmid Institute for Advanced Materials and Nanotechnology
3 Department of Applied Physics [Eindhoven]

Dispersions of rod-like colloidal particles exhibit a plethora of liquid crystalline states, including nematic, smectic A, smectic B, and columnar phases. This phase behavior can be explained by presuming the predominance of hard-core volume exclusion between the particles. We show here how the self-organization of rod-like colloids can be controlled by introducing a weak and highly localized directional attractive interaction between one of the ends of the particles. This has been performed by functionalizing the tips of filamentous viruses by means of regioselectively grafting fluuorescent dyes onto them, resulting in a hydrophobic patch whose attraction can be tuned by varying the number of bound dye molecules. We show, in agreement with our computer simulations, that increasing the single tip attraction stabilizes the smectic phase at the expense of the nematic phase, leaving all other liquid crystalline phases invariant. For sufficiently strong tip attraction the nematic state may be suppressed completely to get a direct isotropic liquid-tosmectic phase transition. Our findings provide insights into the rational design of building blocks for functional structures formed at low densities.

Domaines: Physique [physics]

Andrii Repula, Mariana Oshima Menegon, Cheng Wu, Paul van Der Schoot, Eric Grelet. Directing liquid crystalline self-organization of rod-like particles through tunable attractive single tips. Physical Review Letters, 2019, 122 (12), ⟨10.1103/PhysRevLett.122.128008⟩. ⟨hal-02122886⟩