Basing on the rotational-isomeric-state model and the statistic generator matrix method

the formulas of mean-square dipole moment were deduced in the improved investigation of the disubstituted inorganic polymers

which had considered the dipole moments of both the skeletal bonds and side groups.The revised expression was used to analyze the configurational_conformational dependent dipole moments for the stereoregular and stereoirregular polysiloxane chains

and to compare the mean-square dipole moments of poly(dimethylsiloxane) chain (PDMS) and poly(methlphenylsiloxane) chain(PMPS) with and without considering the side group orientations.The calculated characteristic ratio of mean-square dipole moment for PDMS is in agreement with the experimental data 0.36

which is larger about 46% than the ratio without considering dipole moment of side groups.The temperature coefficient of dipole moment is obtained 1.29×10-3 K-1.The characteristic ratio and its temperature coefficient of for the atactic PMPS (50% i-PMPS) are 0.61 and 1.73×10-3 K-1

respectively.The ratio without considering the side group orientations is 0.20

which is in agreement with the ratio of PDMS without considering the dipole moment of side groups.Following the investigation between PMPS dipole moment and tacticity of chains

it is found that the dipole moment ratio of the syndiotactic PMPS is larger than that of the atactic and isotactic chains

however

its temperature coefficient of the isotactic PMPS is the least.Dependence of the on the first order interaction energy is increasing in the order of the syndiotactic

atactic and isotactic chains.The second order interaction energy has larger effect on for the isotactic and syndiotactic PMPS than that of the atactic chains.