Rheo-Structural Study of Capillary Nanosuspensions

Promovendus/a: Lingyue Liu

Promotor(en): Prof. dr. Erin Koos

Just as water helps sand grains stick together to build sandcastles, my research explores "capillary suspensions" where tiny amounts of one liquid create microscopic bridges between particles suspended in another liquid, forming surprisingly strong networks. The key innovation was adding even smaller particles called nanoparticles to these systems. These particles, millions of which could fit on a single hair, act like nanosized ball bearings when added to the liquid bridges. Using advanced confocal microscopy and rheological equipment, I observed how nanoparticles create thin films on particle surfaces, reduce friction between particles, and promote more uniform distribution of liquid bridges throughout the material.

These materials were subjected to compression, stretching, and shear forces while simultaneously observing microstructural changes. Materials with nanoparticles showed enhanced flexibility during compression, more predictable failure patterns during stretching, and reduced particle movement under shear. Rod-shaped particles were also investigated, revealing that they form directional alignments that create materials with orientation-dependent properties.

My research provides a fundamental understanding of engineering materials with precisely controlled properties. Applications include 3D printing inks that flow smoothly but maintain shape after printing, crack-resistant coatings, lightweight high-strength ceramics, and improved food formulations. By understanding particle interactions at the microscale, materials can be designed with tailored properties, opening pathways to advanced materials, including self-healing systems and structures that adapt based on environmental conditions.