Abstract
The photon transmission technique was used to study the phase transitions of a liquid crystalline acrylate monomer, 6-(4-cyanobiphenyl-4′oxy)hexyl acrylate (LC6), its homopolymer (PLC6) and its graft copolymer (GLC6) with polytetrahydrofuran grafts. The phase transitions were also confirmed by DSC and polarizing microscopy. We observed the phase transition sequence isotropic-nematic-smectic A-smectic C in the LC6 monomer. In PLC6 and GLC6 polymers, the nematic and smectic A phases appear dominant. The apparent nematic-smectic A transition is of first order in PLC6 and of second order in GLC6, with the transition temperature remaining the same. The effects of quenched random constraints introduced in GLC6 are consistent with the theory of quenched random interactions. The critical exponents were also evaluated.
| Original language | English |
|---|---|
| Pages (from-to) | 991-998 |
| Number of pages | 8 |
| Journal | Phase Transitions |
| Volume | 76 |
| Issue number | 12 |
| DOIs | |
| Publication status | Published - 2003 |
Funding
This work was supported by The Scientific and Technological Research Council of Turkey (TUBITAK) under Grant No: TBAG-1951 (100T074), and the Research Fund of Ista_ nbul Technical University, Grant No. 1426 and 1538. This work was performed with partial financial support from the Turkish TÜBITAK and the Italian CNR.
| Funders | Funder number |
|---|---|
| TUBITAK | 1426, TBAG-1951, 1538, 100T074 |
| Türkiye Bilimsel ve Teknolojik Araştirma Kurumu | |
| Consiglio Nazionale delle Ricerche |
Keywords
- Critical exponent
- Graft copolymer
- Liquid crystal homopolymer
- Nematic order
- Photon transmission technique
- Quenched random constraints