Pattern-Stabilized Decorated Polar Liquid-Crystal Fibers

Abstract

Geometric frustration gives rise to new fundamental phenomena and is known to yield the formation of exotic states of matter, such as incommensurate crystals, modulated liquid-crystalline phases, and phases stabilized by defects. In this Letter, we present a detailed study of polar structure of freely suspended fluid filaments in a polarization modulated liquid-crystal phase. We show that a periodic pattern of polarization-splay stripes separated by defect boundaries and decorating smectic layers can stabilize the structure of fluid fibers against the Rayleigh-Plateau instability. The instability is suppressed by the resistance of the defect structure to a radial compression of the cylindrical fibers. Our results provide direct experimental observation of a link between the stability of the liquid fibers, internal polar order, and geometrical constraints. They open a new perspective on a wide range of fluid polar fiber materials.

Labyrinthine instability in freely suspended films of a polarization-modulated smectic phase

“…Labyrinthine structures reversibly disappear during the transition to the nonmodulated phase. This behavior is similar to that of freely suspended filaments formed in the polarization-modulated phase by the investigated material [33]. Furthermore, the instability onset appeared inside the SmC region and was not associated with a phase transition.…”

Nanoparticle Aggregation and Fractal Growth in Fluid Smectic Membranes

“…A theoretical model proposed by Saffman and Delbrück [25,26] and later extended by Hughes, Pailthorpe, and White [27] describes the Brownian diffusion of inclusions in thin membranes embedded in another medium, such as air. Recent experiments have verified these model predictions for the hydrodynamic behavior of micron-size inclusions in fluid smectic films [21][22][23]. There have been several reports on the self-organization of droplets and islands in smectic films [28][29][30] but there are few studies of the diffusion and aggregation of nanoparticles in these systems.…”

“…Liquid crystals, well known for their electrooptic properties and widespread application in displays, exhibit phases with varying degrees of orientational and positional order, making them attractive tools for controlling self-assembly at the nanoscale [19,20]. In addition, the promise of using freely-suspended films as a platform for modeling biological membranes provides a unique motivation for studying hydrodynamics in these essentially two-dimensional fluids [21][22][23]. The ability of smectic A liquid crystals to form inherently stable, thin membranes with quantized thickness has led to several experimental studies of the diffusion of inclusions in films.…”

Nanoscale structures of polarisation-modulated bent-core materials in thin films

“…[3] Examples include the twist-bend nematic phase [3][4][5] characterised by ambidextrous heliconical structure on 10-nm range without layering; the helical nanofilament phase [6] of 30-40 nm wide stack of twisted layers with about 100 nm half pitch and the so-called B7 material [7,8] that forms peculiar micrometre scale helical patterns and slender freely suspended filaments. [9][10][11][12][13][14] The amazing optical B7 textures attracted an intense research that lead to many important findings. [7][8][9]13,[15][16][17][18][19][20][21] Small angle X-ray scattering (SAXS) [7,16,19] studies revealed a number peaks [16,19] that can be indexed by a slightly oblique monoclinic 2D unit cell with a~3-5 nm and b~8-20 nm periodicities.…”

“…[9][10][11][12][13][14] The amazing optical B7 textures attracted an intense research that lead to many important findings. [7][8][9]13,[15][16][17][18][19][20][21] Small angle X-ray scattering (SAXS) [7,16,19] studies revealed a number peaks [16,19] that can be indexed by a slightly oblique monoclinic 2D unit cell with a~3-5 nm and b~8-20 nm periodicities. This can be interpreted either as a columnar [19,21] or as an undulated smectic layer structure [16]; in the columnar model, the layers break into ribbons with half layer steps, whereas the undulated layers are continuous.…”