Speckle reduction in the small-angle light scattering technique using sample vibration

Abstract

Experimental patterns obtained using the small-angle light scattering technique for thin-film polymer studies are fraught with speckles arising from the effect of interspherulitic interference. The presence of speckles hampers efforts in characterizing the spherulitic structure. Using a divergent beam increases the number of scattering sites and results in a reduction of the degree of speckling. Nevertheless, this decimates the ability of analyzing the pattern at low-scattering angles. Employing an expanded collimated beam produces the same effect but necessitates the use of specially designed optical components. This article outlines a novel technique that involves simple vibration of the polymer sample. Experimental results confirm its efficacy in reducing speckles without limiting the ability for analysis at low-scattering angles. © 1997 John Wiley & Sons, Inc.