HYDRODYNAMIC PROPERTIES AND CONFORMATION OF POLY[1-(TRIMETHYLSILYL)-1-PROPYNE] MOLECULES IN SOLUTION

Samples and fractions of poly[1-(trimethylsilyl)-1-propyne] were studi ed by light scattering, translational diffusion measurements, sediment ation, and viscometry. The second virial coefficients and volume swell ing coefficients of these macromolecules were determined. The theory o f translational and rotational friction of persisent wormlike chains w as applied to estimate the equilibrium rigidity of the polymer molecul es. The Kuhn segment length A was found to be (90 +/- 5) x 10(-8) cm. It is shown that the correct estimation of the rigidity and hydrodynam ic diameter of macromolecules requires theoretical consideration of bo th short-range and long-range interactions in a molecular chain. The p resence of alternating double bonds in the backbone chain determines t he enhanced increased rigidity and defines the conformation adapted by the molecules of the considered polymer.