Definition of smectic in English:


Pronunciation /ˈsmektik/ /ˈsmɛktɪk/


  • Denoting or involving a state of a liquid crystal in which the molecules are oriented in parallel and arranged in well-defined planes.

    Compare with nematic

    ‘Our results suggest that of the multiple structures which different monolayers form when supercompressed, pulmonary surfactant collapses by the same mechanism as other compounds that form smectic liquid-crystal bulk phases.’
    • ‘Molecules in the smectic phase have orientational as well as a small amount of positional order.’
    • ‘Hydrated phospholipids themselves are liquid-crystals, and in these multiple respects, their behavior resembles that of at least some other compounds that form smectic bulk phases.’
    • ‘A liquid crystal device is constituted by a chiral smectic liquid crystal to form a plurality of pixels.’
    • ‘From our measurements of fluctuations, we obtain the product of the bilayer bending modulus K C and the smectic compression modulus B.’


  • A smectic substance.

    ‘There also exists higher order smectics which form layers with positional ordering within the layers.’
    • ‘We outline the possible experimental significance of our findings for the rheology of both aligned and polydomain smectics.’
    • ‘We find that the quantum smectics are rather different from the usual classical smectics in that the density correlations along the direction of the stripes manifest a Bragg-Glass type behaviour whereas those in the transverse direction are infra-red divergent.’
    • ‘I am using the hydrodynamic equations for smectics A to predict the results of these experiments, which are being performed by a colleague, Professor Stephen Kevan.’
    • ‘The winner, in a 1998 Physical Review Letters article co-authored with his wife Dr Mirjana Golubovic, has identified this phase as the very first realization of a new state of matter: the sliding phase of weakly coupled two-dimensional smectics of DNA molecules sandwiched between lipid membranes, that themselves form a layered three-dimensional lamellar phase.’


Late 17th century via Latin from Greek smēktikos ‘cleansing’ (because of the soaplike consistency).