Low‐angle light scattering of ionotropic gels

Abstract

Low‐angle light‐scattering patterns were obtained on ionotropic gels formed by the diffusion of Ca++ into a polygalacturonate sol. Near the sol–gel boundary, diffraction patterns were obtained which indicated organized structures with repeating units of 1100, 250, and 12.5 μ. Microscopic investigations confirmed that at this gel boundary capillaries run parallel to each other and perpendicular to the direction of diffusion. The diameter of capillaries was 12 μ while their length was in the 1000 μ range. Short interconnecting capillaries were about 200–300 μ in length. Inside the gel, in the more highly crosslinked parts, a disorientation occurs during the aging process with the partial disappearance of capillaries. However, at the gel–sol and gel–semipermeable membrane boundaries, the highly organized structures remain even during prolonged aging. The kinetics of the gel formation was also investigated.

Laser‐diffraction Patterns of Highly Ordered Superstructures in the Lenses of Bovine Eyes

“…It has been previously shown that light scattering is an effective technique in the determination of structure and order in gel matrices.1-6 The advantage of using light scattering over electron microscopy is twofold: (1) both large and small superstructures can be observed, depending upon the angle of observation, and (2) no artifacts are introduced because of the use of preparative or staining devices.…”