ქიმიის ტერმინთა განმარტებითი ლექსიკონი

Mesophase with a helicoidal supramolecular structure in which blocks of molecules, with a local structure of the smectic A type, have their layer normals rotated with respect to each other and are separated by screw dislocations.

Note 1: See Fig. for an illustration of the molecular arrangement of a TGBA^* mesophase.

Note 2: The TGBA^* mesophase is formed by a chiral compound or a mixture of chiral compounds.

Note 3: Two TGBA^* structures are possible; in one, the number of blocks corresponding to a rotation of the layer normal by 2p is an integer, while in the other, it is a non-integer.

Note 4: A TGBA^* is found in a phase diagram between smectic A and chiral nematic mesophases or between a smectic A mesophase and an isotropic phase.

Note 5: The temperature range of existence of a TGBA^* mesophase is typically several K.

Fig. Illustrating the structure of a TGBA^* mesophase corresponding to half of the full helical twist.