Imaging the Pore Structure of Geological Materials with Bifunctional Nanoparticles

Analysis of complex pore structure of geomaterials is a fundamental issue in geoscience. Here bifunctional nanoparticles with magnetic and fluorescent properties are introduced as novel markers for optical imaging of pore structure in geomaterials. Using the paramagnetic property, powder of the nanoparticle is driven into pores under an external magnetic field, avoiding a tedious sample preparation and eliminating artificial damage of sample preparation in conventional methods. Meanwhile, the fluorescent nanoparticle marker offers a sharp contrast imaging between the rock matrix (black) and pores (bright) under microscopy. Furthermore, fluorescent nanoparticles with different sizes and colors are designed to demonstrate the potential of the method for describing pore throat sizes. Combining the merits of the paramagnetic and fluorescent properties of nanoparticles, a convenient and practical sample preparation is proposed to promote optical imaging analysis of the pore structure in geomaterials.