Role of shape anisotropy on nanoparticle self assembly at liquid/liquid interface

The structural arrangement of molecules at liquid interfaces gives rise to a diverse range of behaviors in soft matter systems. Interfacial tension plays a fundamental role in this context. The precise measurement of interfacial tension is a critically important endeavor, essential both to the field of science and various industries. These methodologies and their attributes are extensively discussed by Drelich et al.[1]. In this study, we employed pendant drop tensiometry to measure the dynamic surface tension of a dodecane drop in a nanoparticle solution environment. We compared the effect of spherical (AuNP) and rod-shaped (AuNR) particles at the dodecane/water interface. Surface tension profiles for AuNRs reached saturation for all experimental concentrations, while AuNPs exhibited a continuous decline until a higher concentration. An analysis of dynamic surface tension variations over time revealed distinct stages, including nanoparticle diffusion, interface adsorption, and layer formation. We conducted supporting analytical calculations to address various parameters, including diffusion rates, detachment energy, and interactions with both the interface and the particles.

References

[1] J. Drelich, C. Fang, and C. L. White, Encyclopedia of Surface and Colloid Science, 3, 3158 (2002).