The dielectric properties of proteins in polar solvents have been extensively studied, and recently some linear polyelectrolytes-nucleic acids, nucleohistone, and hyaluronic acid-in polar solvents have been investigated at this l a b o r a t~r y .~-~ Most proteins studied have been highly polar and belong to the relatively small group of substances which give dielectric increments in solution. This is also the case for the linear macromolecules mentioned above, and these are still more polar so that they may be investigated in very dilute solutions. For these substances with axial ratios exceeding 10: 1, it was possible to calculate molecular weights from the relaxation times obtained dielectrically. --6 A number of polyelectrolytes have similar pliysicochernical properties aiid are better defined chemically and might thus serve as "model substances" for dielectric investigation. Though it may not be looked upon as a dipolar ion, the sodium salt of a carboxymethylcellulose (CMC) was chosen for this study. EXPERIMENTALA pharmaceutical sample of CMC (kindly supplied by AB Hassle, HEssleholm, Sweden) was purified by centrifuging a 1% solution at 20,OOOg for 1 hour to remove a slight amount of insoluble material, followed by dialysis against distilled water. The "salt-free" solution was then freezedried. The white porous material obtained had a moisture content of 7.4% (the specimen was dried at 95°C. and 0.1 mm. Hg over phosphorus pentoxide for 20 hours). The sodium content of the "moisture-free" substance was 5.78% (determined with flame photometer), corresponding to a ratio of carboxymethylglucose to glucose in CMC close to 1 : 1 if the sodium found is assumed to correspond to the carboxyl groups only, which seems reasonable when considering the pretreatment of the specimen.The viscosity of CMC (specimen IV) in aqueous solutions below 0.1% (20 "C. in an Ostwald viscometer) showed similar dependence upon concentration as for other polyelectrolytes, vs,/c varying between 35 (0.1%) and 50 (0.02%) and falling again at still lower concentrations (c = concentration in grams per 100 ml.).The solutions investigated were prepared by dissolving weighed amounts of substance in redistilled water, using a shaking machine. Complete dis-229

Specimens of sodium alginate have been investigated dielectrically in aqueous solution at low concentrations. The effect on the dielectric increment and dispersion of concentration of polyions and counterions, isoionic dilution, degree of polymerization and degree of neutralization of polyions, and the dielectric constant of the solvent has been studied mainly. Qualitative interpretation of the data in accordance with the present polyelectrolyte theory as Maxwell‐Wagner or Debye‐Falkenhagen effects has been attempted.