Raman imaging for measuring homogeneity of dry binary blend: Combining microscopy with spectroscopy for technologists

Expanding the capabilities of Raman scattering as an analytical tool for engineering applications can optimize the technological output immensely. Understanding the homogeneity of any blended mix is one such significant parameter in the family of composite building construction materials that needs an appropriate tool for its measurement. Raman spectromicroscopy has been established here for the purpose of studying the chemical homogeneity at the microscopic scale of a dry binary blend used in the building constructions as an example. In this study, two waste stone powdered materials, obtained from western Indian stone fields, have been characterized in their respective unmixed forms using Raman spectroscopy up to an extent so that the same can be developed as a microscopic tool to clearly "see" the chemical homogeneity of a mixture. A step-by-step study has been carried out by first, simply making a physically separated and identifiable boundary of the two materials followed by obtaining a Raman line image. The Raman line map could clearly identify the boundary, which otherwise was not possible to appreciate visibly. The same recipe has been extended to study the homogeneity of a binary mixture (blended in 1:1 ratio), using a Raman area map. The novelty of the work lies in the advancement in the analytical tool's family to see the chemical homogeneity of building construction materials at the microscopic level. Chemical imaging using Raman spectroscopy has been demonstrated as a simple tool to understand the homogeneity of the dry binary blend, which was not possible by other simple techniques. Using Raman area mapping proves to be a quick, valuable, and effective tool for measuring the homogeneity of the blended mixes at the microscopic scale and important for application in building construction materials.