Structure of twist-grain-boundary–Cphases

Giant-block twist grain boundary smectic phases.

Study of a diverse set of chiral smectic materials, each of which has twist grain boundary (TGB) phases over a broad temperature range and exhibits grid patterns in the Grandjean textures of the TGB helix, shows that these features arise from a common structure: "giant" smectic blocks of planar layers of thickness l(b) > 200 nm terminated by GBs that are sharp, mediating large angular jumps in ...

Missing-atom structure of diamond Sigma 5 (001) twist grain boundary

On the Optics of Twist Grain Boundary Smectics

We have studied theoretically the optical properties of twist grain boundary

Rheology of twist-grain-boundary-A liquid crystals.

We report studies on the rheological properties of a liquid crystalline analog of Abrikosov phase in type-II superconductors known as twist-grain-boundary-A (TGB(A)) phase. The TGB(A) phase shows a large apparent yield stress compared to the cholesteric (N*) phase. The storage modulus (G') of the TGB(A) phase is significantly larger than the loss modulus (G''). The dynamic relaxation measuremen...

Twist-grain-boundary transitions in a chiral tolane compound

High resolution calorimetric studies have been carried out on the chiral compound methylheptyloxydi ̄ uorooctyloxybenzoyloxytolane (8BTF2O1M7 ). The tilt tendency is greater in this compound than in several other structurally similar ̄ uorinated tolane liquid crystals, and it exhibits tilted chiral smectic C (SmC*) and tilted twist-grain-boundary (TGBC) phases but not the untilted SmA or TGBA pha...