ABSTRACT:Thermotropic liquid crystalline and photoluminescent properties of semi-rigid homo-and copoly(ester imide)s composed of only both 3,3 ,4,4 -biphenyltetracarboxdiimide and aliphatic chains without traditional mesogens, which were prepared by transesterification of N, N -bismethyl ester derivatives and N, N -bisalcohols of 3,3 ,4,4 -biphenyltetracarboxdiimide, were evaluated by differential scanning calorimetry (DSC), polarizing microscope observation, powder X-Ray analyses, UV-vis absorption and PL spectrum measurements. These measurements suggested that polymers having decamethylene chain neighboring the imide ring and decamethylene chain-rich copolymers tend to form nematic phase and that they show maximum absorbances and blue-emission maxima arising from the 3,3 ,4,4 -biphenyltetracarboxdiimide both in solutions and in films.KEY WORDS Liquid Crystalline Property / Photoluminescent Property / Semi-Rigid Poly(ester imide) / 3,3 ,4,4 -Biphenyltetracarboxdiimide / Transesterification / Nematic Phase / Differential Scanning Calorimetry / Blue-Emission / Polyimides have not only excellent thermal, mechanical and chemical properties, but also various interesting physical properties such as nonlinear optical, liquid crystalline (LC) and fluorescent properties. [1][2][3][4]34 Active works about synthesis and LC properties of the polyimides have been done by Kricheldorf and so on. [5][6][7][8][9][10][11][12][13][14][15][16] We have also continued to prepare a series of semi-rigid thermotropic LC poly(ester imide)s and poly(imide carbonate)s and to discuss a relationship between polymer structure and LC property in the semi-rigid polyimides. [17][18][19][20][21][22][23][24][25][26][27][28][29][30] There are basically two different approaches in order to obtain the thermotropic LC polyimides. The first approach is to prepare polymers constituted of symmetric aromatic diimide units such as 3,3 ,4,4 -biphenyltetracarboxdiimide and 3,3 ,4,4 -p-terphenyltetracarboxdiimide, and the seconds is to synthesize polymers having asymmetric aromatic imide structures like N-phenylphthalimide. The former polymer has low or poor mesogenic property compared with the latter. Most of them don't show LC properties without the presence of benzene ring next to the imide ring or conventional biphenyl mesogen in the main chain. The 3,3 ,4,4 -p-terphenyltetracarboxdiimide unit is a better mesogen than the 3,3 ,4,4 -biphenyltetracarboxdiimide. 26,27 In recent years, we developed semi-rigid homo-and copoly(imide carbonate)s made up of only the symmetric diimides (3,3 ,4,4 -biphenyltetracarboxdiimide and/or 3,3 ,4,4 -p-terphenyltetracarboxdiimide) and aliphatic chains without coexistence of the biphenyl moiety in the main chain and showed that the 3,3 ,4,4 -p-terphenyltetracarboxdiimide-rich polymers form thermotropic LC phases in spite of absence of the conventional mesogens. 28,29 The aliphatic chains next to the imide ring play an important role in the LC formation of the semi-rigid poly(imide carbonate)s. Kricheldorf et al. found that...