Control of monodomain polymer-stabilized cuboidal nanocrystals of chiral nematics by confinement.

Journal Article · Tue Oct 26 00:00:00 EDT 2021 · ACS Nano

DOI:https://doi.org/10.1021/acsnano.1c04231· OSTI ID:1847945

Sadati, Monirosadat; Martinez-Gonzalez, Jose A.; Cohen, Alexander; Norouzi, Sepideh; Guzman, Orlando; de Pablo, Juan J.

Liquid crystals are important components of optical technologies. Cuboidal crystals consisting of chiral liquid crystals-the so-called blue phases (BPs), are of particular interest due to their crystalline structures and fast response times, but it is critical that control be gained over their phase behavior as well as the underlying dislocations and grain boundaries that arise in such systems. Blue phases exhibit cubic crystalline symmetries with lattice parameters in the 100 nm range and a network of disclination lines that can be polymerized to widen the range of temperatures over which they occur. Here, we introduce the concept of strain-controlled polymerization of BPs under confinement, which enables formation of strain-correlated stabilized morphologies that, under some circumstances, can adopt perfect single-crystal monodomain structures and undergo reversible crystal-to-crystal transformations, even if their disclination lines are polymerized. We have used super-resolution laser confocal microscopy to reveal the periodic structure and the lattice planes of the strain and polymerization stabilized BPs in 3D real space. Our experimental observations are supported and interpreted by relying on theory and computational simulations in terms of a free energy functional for a tensorial order parameter. Simulations are used to determine the orientation of the lattice planes unambiguously. The findings presented here offer opportunities for engineering optical devices based on single-crystal, polymer-stabilized BPs whose inherent liquid nature, fast dynamics, and long-range crystalline order can be fully exploited.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: National Science Foundation (NSF); USDOE Office of Science - Office of Basic Energy Sciences - Experimental Program to Stimulate Competitive Research (EPSCoR); USDOE Office of Science - Office of Basic Energy Sciences - Materials Sciences and Engineering Division
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 1847945
• Journal Information: ACS Nano, Vol. 15, Issue 10
• Country of Publication: United States
• Language: English

Related Subjects

confocal microscopy
stabilized blue-phases
confinement
liquid crystals
photonic soft crystals