Novel liquid-crystalline polymeric materials via noncovalent grafting: Hydrogen-bonded complexes with poly(4-vinyl pyridine)
- Universite Laval (United Kingdom)
A new type of liquid crystalline polymeric material can be formed by mixing a classical small molecule liquid crystal, which has been functionalized by a strongly polar, ionic or ionisable group, with a polymer possessing complementary groups. Noncovalent {open_quotes}grafting{close_quotes} of the small molecule mesogen to the polymer can then take place through hydrogen-bonding or electrostatic interactions. The authors have end-functionalized a 4,4`-n-alkoxy-biphenyl mesogen with a carboxylic acid group, and mixed it with poly(4-vinyl pyridine). FTIR spectroscopy clearly shows that hydrogen-bonding takes place between the two species. Differential scanning calorimetry, polarizing optical microscopy and X-ray scattering studies show that the disordered smectic phase which exists in the functionalized liquid crystal alone is thermally stabilized when mixed with the polymer, and an ordered mesophase present in the liquid crystal disappears in the mixtures, at molar ratios of liquid crystal to polymer repeat unit of less than 1. Dynamic mechanical analysis, possible for mixtures with molar rations of 0.1 or less, show that the glass transition temperature of the polymer decreases by 80{degrees}C up to a molar ratio of 0.02, confirming the effectiveness of the interactions between the two species. No further decrease occurs at higher molar ratios, due to formation of the solid phase of the liquid crystalline material.
- OSTI ID:
- 141718
- Report Number(s):
- CONF-930304-; TRN: 93:003688-1401
- Resource Relation:
- Conference: 205. American Chemical Society national meeting, Denver, CO (United States), 28 Mar - 2 Apr 1993; Other Information: PBD: 1993; Related Information: Is Part Of 205th ACS national meeting; PB: 1951 p.
- Country of Publication:
- United States
- Language:
- English
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