On the basis of rotational isomeric state (RIS) theory

the first-order

second-order

and third-order conformational energies were calculated for poly(oxyethylene)\[(CH2—CH2—O)x] (POE)chain using semiempirical potential function.Configuration-dependent properties of POE chains

such as the characteristic ratio r2>/nl2

the dipole moment ratio μ2>/nm2 and their temperature coefficients dln r2>/dT and dln μ2>/dT

were calculated using the statistical weight matrix method

where r2> in the meam-square end-to-end distance

μ2> is the meansquare dipole moment

n means the length of chain

l and m are the bond length and bond dipole moment

respectively.Results showed that

for long POE chainsr2>/nl2=4.9

dlnr2>/dT=-1.5×10-3K-1

μ2>/nm2/nm2=0.49

and dlnμ2>dT=2.8×10-3K-1.All these values are better than tose obtained from the second-order interaction approximation

and the characteristic ratio and the dipole moment ratio are in good agreement with early experimental findings.