Stiffening of Metallic Gallium Particles by Entrapment of Organic Molecules

This work describes stiffness measurements of gallium particles that include entrapped organic molecules, using PeakForce Tapping technology, particularly PeakForce QNM (Quantitative Nanomechanical) characterization. The composite particles were formed by ultrasonic irradiation of molten gallium in decane or in aqueous solutions of three organic compounds: phenanthroline, Congo red, or crystal violet. It was found that the Ga particles formed in the aqueous solutions of the organic compounds demonstrated very similar stiffness values, regardless of the identity of the organic compound. Moreover, those stiffness values were ca. 5 times higher than the stiffness of the Ga particles formed in pure decane. We attribute the superior stiffness to the formation of hybrids in which the organic molecules were partially incorporated within the crystal lattice of the gallium particles.