Use this URL to cite or link to this record in EThOS:
Title: Dynamic and static conformations at the water-solid interface
Author: Poetes, Rosa
ISNI:       0000 0004 5364 562X
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2014
Availability of Full Text:
Access from EThOS:
Full text unavailable from EThOS. Please try the link below.
Access from Institution:
In this work, we have explored dynamic and static phenomena occurring at the watersolid interface. Controlling the interaction of solids with water is technologically very interesting. Applications include the inside coating of pipes, containers and medical equipment and coating of boats, windows and underwater equipment. In Part I, we explore the possibility of using low cost and practical triggering mechanisms for fast and reliably switching of the surface wettability in the liquid environment. Electric fields are used as triggers to change the surface properties of charged polymer brushes and hydrogels in water. The response of surface-attached polymers to the external triggers was studied in detail. We showed that neither charged polymer brushes nor hydrogels are easily exploitable for surface property tuning using electric potentials as switching mechanisms. The two limiting factors for the use of polymer brushes and hydrogels in such systems are the material instability and the low switching speed between swollen and collapsed conformations. While the stability issues could be resolved through further work on the synthetic side, we believe that the long switching times necessary for complete conformational changes are an inherent problem of these densely grafted systems and due to entanglements. Part II focuses on the influence of structure on surface wettability. Metastable selfcleaning wetting behaviour of water droplets on hydrophilic surfaces was studied. We confirmed and expanded the design parameters for very robust metastable Cassie- Baxter wetting states with high contact angles on hydrophilic surfaces, which were introduced by Tuteja et al. [1]. The fundamental difference in the wetting behaviour of disconnected and connected structures was also shown. The behaviour of superhydrophobic surfaces under water in an open system was also studied. The decay of the air bubble covering the superhydrophobic material (plastron) was quantified for different materials. A strongly non-linear depth dependence of the plastron stability was shown. The limited plastron life-time makes the use of superhydrophobic surfaces for underwater applications (buoyancy increase or drag reduction) technologically challenging.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral