TY - JOUR
T1 - Towards supramolecular side-chain liquid crystal polymers - 4. Blends of low molar mass mesogens with amorphous polymers
AU - Stewart, David
AU - Paterson, Brian J.
AU - Imrie, Corrie T.
N1 - We are pleased to acknowledge support from the EPSRC, grant number GR/J32701, and the University of Aberdeen Research Committee for the award of a grant to purchase the PL-DSC.
PY - 1997/3/1
Y1 - 1997/3/1
N2 - The thermal behaviour of blends of two low molar mass mesogens, 6-(4-methoxyazobenzene-4′-oxy)hexanoic acid, 1, and 6-(4-methoxyazobenzene-4′-oxy)hexane, 2, with polystyrene (PS), poly(4-vinyl pyridine) (P4VP) and poly(2-vinyl pyridine) (P2VP) has been characterised. 1 and 2 are enantiotropic nematogens; the clearing temperature of 1 is considerably higher than that of 2. This is attributed to the ability of 1 to form hydrogen-bonded dimeric materials. 1 is essentially immiscible with PS and thus, the transition temperatures are independent of blend composition. In contrast, a strong modification of the transition temperatures is observed on blending 1 with either P4VP or P2VP. Molecular mixing occurs in these blends below approximately 0.2 mole fraction acid. 2 is essentially immiscible with both P4VP and P2VP. The miscibility of 1 with P2VP and P4VP may be attributed therefore to the formation of hydrogen-bonded complexes. Phase separation occurs on increasing the acid concentration and this is attributed, in part, to the interaction between the mesogenic unit and the pyridyl groups. The relevance of this observation to the design of supramolecular liquid crystal polymers is discussed.
AB - The thermal behaviour of blends of two low molar mass mesogens, 6-(4-methoxyazobenzene-4′-oxy)hexanoic acid, 1, and 6-(4-methoxyazobenzene-4′-oxy)hexane, 2, with polystyrene (PS), poly(4-vinyl pyridine) (P4VP) and poly(2-vinyl pyridine) (P2VP) has been characterised. 1 and 2 are enantiotropic nematogens; the clearing temperature of 1 is considerably higher than that of 2. This is attributed to the ability of 1 to form hydrogen-bonded dimeric materials. 1 is essentially immiscible with PS and thus, the transition temperatures are independent of blend composition. In contrast, a strong modification of the transition temperatures is observed on blending 1 with either P4VP or P2VP. Molecular mixing occurs in these blends below approximately 0.2 mole fraction acid. 2 is essentially immiscible with both P4VP and P2VP. The miscibility of 1 with P2VP and P4VP may be attributed therefore to the formation of hydrogen-bonded complexes. Phase separation occurs on increasing the acid concentration and this is attributed, in part, to the interaction between the mesogenic unit and the pyridyl groups. The relevance of this observation to the design of supramolecular liquid crystal polymers is discussed.
UR - http://www.scopus.com/inward/record.url?scp=0000816346&partnerID=8YFLogxK
U2 - 10.1016/S0014-3057(96)00157-7
DO - 10.1016/S0014-3057(96)00157-7
M3 - Article
AN - SCOPUS:0000816346
SN - 0014-3057
VL - 33
SP - 285
EP - 290
JO - European Polymer Journal
JF - European Polymer Journal
IS - 3
ER -