Smectic I phase

At 77.67°C the two surface monolayers are in the smectic-I phase and the three interior layers are in the smectic-C phase. 

SmB SmC SmC SmCA SmCPA SmCPp SmCo, SmIA SmX UCST XRD Smectic B phase Smectic C phase (synclinic tilted smectic C phase) Chiral (synclinic tilted) smectic C phase Chiral anticlinic tilted (antiferroelectric switching) SmC phase Antiferroelectric switching polar smectic C phase Ferroelectric switching polar smectic C phase Chiral smectic C alpha phase Chiral antiferroelectric switching smectic I phase Smectic phase with unknown structure Upper critical solution temperature X-ray diffraction... 

Figure 5 Photomicrographs of liquid crystal textures seen in the polarizing microscope. (A) The Schlieren texture of a smectic I phase. (B) The focal conic texture of a chiral smectic C phase, which has a helical structure, forming at a transition from the liquid. The pitch of the helix shows up as parallel lines that are parallel to the molecule layers (each line corresponds to about a thousand molecular layers). The pitch lines reflect accurately the layer structure in the focal-conic domain. (A) Courtesy of JW Goodby, University of Hull, UK, with permission. (B) Reproduced with permission from Gordon and Breach, Switzerland.)...

By mixing a chiral liquid-crystal compound with its optical antipode, systems possessing arbitrary values of the enantiomeric excess can be designed. If a chiral compound shows smectic-C and smectic- I phases, the racemate, i.e., the 1 1 mixture of the two antipodes, also exhibits these phases but the ferroelectric properties of the smectic-C phase and the electroclinic effect in the smectic- phase are lost. This offers the unique possibility to study a given system with and without ferroelectridty or with a variable markedness of its ferroelectric properties. 

The structure of the chiral smectic F phase is similar to that of the chiral smectic I phase, except that the tilt direction is towards the side of the local hexagonal packing net, rather than towards the apex. 

Frederiks transition in the hexagonal smectic I phase (and also in the smectic C phase with a weak hexagonal order [163]) has... 

The molecules in the smectic I phase, like the smectic C and hexatic B phases, are expected to be in dynamic motion about their long axes, presumably on a similar time scale. The rotation is expected to be of a cooperative nature as the molecular centres are separated by only 0.4-0.5 nm. 

The smectic F phase can also be considered as a tilted hexatic phase similar to the smectic I phase, the difference between the two phases lying in the direction of the long molecular axes with respect to the two-dimensional arrangement within the smectic layers [151]. Calorimetric and X-ray diffraction studies of several compounds of the homologous TBnA series carried out around the SmC-SmF transition clearly indicate the first order nature of the corresponding transition, with, in particular, a jump in the... 

If, instead of pointing towards the side of the hexagons, the tilt points towards the apices of hexagonal net, one obtains a new phase the smectic I phase (Fig. 2.10(b)). Differences in the in-plane correlation length also arise, those within a layer in the Si phase being greater. 

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