Observation of transition cascades in sheared liquid crystalline polymers

Abstract

We observe anomalous shear thickening behavior of a lyotropic liquid crystalline polymer due to the dynamics of the nematic director.

Existence and Stability of Kayaking Orbits for Nematic Liquid Crystals in Simple Shear Flow

“…The limiting case is logrolling, a stationary state where the principal axis of the rod ensemble collapses onto the vorticity axis, while wagging corresponds to oscillations (but not complete rotations) of the molecular orientation in the shear plane about some mean angle, although wagging regimes do not appear in our analysis. We note very recent experimental results [31] coupled with the high-resolution numerical results of the Doi-Hess kinetic theory [30] that provide overwhelming evidence that the kayaking orbit is responsible for the anomalous shear-thickening response of a high aspect ratio, rodlike, liquid crystal polymer with the acronym PBDT. The papers [27,31] give extensive lists of literature references.…”

“…We note very recent experimental results [31] coupled with the high-resolution numerical results of the Doi-Hess kinetic theory [30] that provide overwhelming evidence that the kayaking orbit is responsible for the anomalous shear-thickening response of a high aspect ratio, rodlike, liquid crystal polymer with the acronym PBDT. The papers [27,31] give extensive lists of literature references.…”

Existence and stability of kayaking orbits for nematic liquid crystals in simple shear flow

“…The limiting case is logrolling, a stationary state where the principal axis of the rod ensemble collapses onto the vorticity axis, while wagging corresponds to oscillations (but not complete rotations) of the molecular orientation in the shear plane about some mean angle, although wagging regimes do not appear in our analysis. We note very recent experimental results [25] coupled with the high-resolution numerical results of the Doi-Hess kinetic theory [24] that provide overwhelming evidence that the kayaking orbit is responsible for the anomalous shear-thickening response of a high aspect ratio, rodlike, liquid crystal polymer with the acronym PBDT. The papers [21], [25] give extensive lists of literature references.…”

“…We note very recent experimental results [25] coupled with the high-resolution numerical results of the Doi-Hess kinetic theory [24] that provide overwhelming evidence that the kayaking orbit is responsible for the anomalous shear-thickening response of a high aspect ratio, rodlike, liquid crystal polymer with the acronym PBDT. The papers [21], [25] give extensive lists of literature references.…”

Shear-Induced Isotropic–Nematic Transition in Poly(ether ether ketone) Melts

“…(III) For γ̇ > 20 s –1 , the entire sample is nematic, exhibiting a shear-thinning regime with η ≈ γ̇ –0.5 , as nematic phases seem to invariably display. ,,,,− …”