We study the thermodynamics and single-chain statistics of wormlike polymer solutins with Maier-Saupe-type interactions using self-consistent-field (SCF)theory.The SCF equatins are derived usign a systematic field-theoretical approach which yields the SCF equatios as the lowest order approximation,but permits fluctuation corrections to be incorporated.We solve the SCF equations usign the spherolidal functions,which provides a nonpeturbative description of the thermodynamics and single-china statistics in the nematic atate for arbitrary degrees of nematic order.Several types of phase diagrama are predicted,wtih an emplhasis on the limit of metastability (spinodal)associated with each phase.The shape and location of these spinodals suggest interesting scenarios for the phase transition kinetics.A large but finite persistence length is shown to significatly decrease the isotropic-nematic transition temperature relative to that for rigid rods.In the nematic state,the mean-square end-to-end distrance in the paralled and perpendicular directions are governed by two separate correlation lengths.An exact relationship between these correlation lengths and the eigenvalues of the spheroidal functions is provided,which eproduces the analytical expressions predicted from earlier studies in hte limit of large nematic strength.The dominant contribution to the single-chain thermodynamicis is shown to arise from small amplitude undulations in th directios perpendicular to the nematic direction;the presence of hairpins,though crucial for determining the dimensions of the polymer,has insignificant consequences on the signle-chain thermodynamics.
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