1992 Fiscal Year Final Research Report Summary
STUDY ON SYNTHESIS CYCLOTRIPHOSPHAZENE DERIVATIVES AND ITS MESOGENICITY
| Project/Area Number |
03650650
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
工業物理化学・複合材料
|
|---|
| Research Institution | GIFU UNIVERSITY |
|---|
Principal Investigator |
MORIYA Keiichi ASSOCIATE PROFESSOR, 工学部, 助教授 (40174461)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
YANO Shinichi PROFESSOR, 工学部, 教授 (70021607)
|
|---|
| Project Period (FY) |
1991 – 1992
|
| Keywords | CYCLOTRIPHOSPHAZENE / LIQUID CRYSTALLINE / PHASE TRANSITION / SMECTIC C PHASE |
|---|
| Research Abstract |
1) A series of hexakis(4-(4'-alkoxy)biphenoxy)cyclotriphosphazene(PN(OC_6H_4C_6H_4OC_nH_<2n+1>)_2)_3(n=6-12) with alkyl chains at the end of biphenyl ring was synthesized and we studied their liquid crystallinity and phase transition by the use of orthoscope image of polarizing microscope observation and DSC, X-ray and FT-IR measurements. We found a monotropic Smectic C phase in n=6 at 453 K, enantiotropic Smectic C and Nematic phase in n=7 and enantiotropic Sc phase in n=8-12^1. A melting points and clearing points lower with an increase of n showing a slight odd-even effects. Temperature dependence of powder X-ray measurements of n=8 shows a new peak at 2theta=4.1ﾟ with a strong intensity at Sc phase. The results shows a long phase separation of 37 A and corresponds to phase separation of Sc phase. The computer calculation under the assumption of all trans conformation of alkyl groups on the basis of the crystal structure of hexakisbiphenoxy-cyclotriphosphazene gives the long axis of 40 A. In this case cyclotriphosphazene has three alkoxybiphenyl groups in both side of the phosphazene ring almost in perpendicular. Each three biphenoxy groups bend each other slightly and this bend generates the slight inclined layer structure of Smectic C phase. This is the model of liquid crystalline state of cyclotriphosphazene. The temperature dependence of FT-IR measurements give lower frequency shift of P=N and P-O(-C) stretching vibrations at crystalline-liquid crystalline phase transition. This shows that a strength of the bonds of P=N and P-O(-C) weaken at melting points.
2) The introduction of octoxyphenyl to biphenyl ring in the cyclotriphosphazene gives no liquid crystalline state by use of DSC measurements and polarizing microscope observation. The results shows that alkoxyphenyl groups are still too short to generate the layer of liquid crystalline of cyclotriphosphazene.
|
