Determination of Chitosan Scattering Parameters by Using Multi Angle Static Laser Light Scattering(MASLLS )

Abstract

Measurement of polymer characteristics by using the static laser light scattering experiment needs a precisedetermination of its refractive index increment, dn/dc. Through the dependence of Rayleigh scattering coefficient on the squarevalue of the refractive index increment(dn/dc)2. The average molecular weight of the investigated polymer is determined using ahome built of Mach-Zehender Interferometer(MZI) which has been constructed to measure the refractive index, n, of Chitosan atdifferent concentration ranging from 0.002 to 0.008 gm/L. The measurements are carried out through the dependence of fringenumbers on the laser incidence angle of polymer’s solutions. The used laser beam is a He-Ne laser with 543 nm wavelength and2mw in power (from Meridith). The obtained value of dn/dc is 0.198011 L/gm . A static laser light scattering(SLLS) experimentis constructed in our lab to measure the angular distribution of the scattered laser light intensity. From which the Rayleigh ratioRθ, molecular weight MW, second virial coefficient A2 and the square radius of gyration are calculated through what iscalled as Zimm plot method .