A. Catarina C. Esteves

Temperature-Triggered Collection and Release of Water from Fogs by a Sponge-Like Cotton Fabric

A sponge-like cotton fabric autonomously collects and releases water from fogs triggered by typical day-and-night temperature variations. The reversible switching between absorbing-superhydrophilic/releasing-superhydrophobic states results from structural changes of a temperature-responsive polymer grafted on the very rough fabric-surface. This material and concept presents a breakthrough into simple and versatile solutions for collection, uni-directional flow, and purification of water captured from the atmosphere.

Nucleation and Growth of Monodisperse Silica Nanoparticles

Although monodisperse amorphous silica nanoparticles have been widely investigated, their formation mechanism is still a topic of debate. Here, we demonstrate the formation of monodisperse nanoparticles from colloidally stabilized primary particles, which at a critical concentration undergo a concerted association process, concomitant with a morphological and structural collapse. The formed assemblies grow further by addition of primary particles onto their surface. The presented mechanism, consistent with previously reported observations, reconciles the different theories proposed to date.

Time-resolved surface rearrangements of polymer films monitored by dynamic recovery contact angle (DRCA)

Polymer surfaces can be designed to have functionalities significantly different from the bulk. However, such surfaces can be very dynamic in nature and rapidly rearrange or exchange with bulk components upon changing environmental conditions or contacts. The time-frames involved in surface rearrangements of polymer films are investigated by Dynamic Recovery Contact Angle (DRCA) through a simple, non-invasive and reconstructive approach, based on the sequential exchange of the polymer surface contact between a probe liquid (water) and air.