[nanoPost] Hydrophilic and hydrophobic surfaces

University UK
The research group developed a technology to modify surfaces and interfaces. 

The technology takes the form of a polymer additive which may be modified to render surfaces either hydrophilic or hydrophobic. The additive can be tailored to render it compatible with conventional bulk thermoplastics but also incorporates structural modifications to confer surface active properties which might be tailored to a broad range of applications.
At present they have shown this additive to be extremely effective at modifying an air/polymer interface when added to bulk polymer in relatively low quantities, i.e. a few percent. The chemical structure of the additive is highly flexible suggesting that it may be modified for use in a variety of applications. They are commencing the commercialisation process and starting to talk to a number of companies with regards to applications for what is potentially a broad generic technology.
Technology Summary
The first series of additives, designed as proof of principle additives were decorated with a number of fluoroalkyl groups with aim of rendering polymer surfaces both hydrophobic and lipophobic. It was found that the multiple functionalities result in such high surface activity that when the additive is present in as little as five percent by weight, the bulk polymer possessed surface properties approaching those of PTFE.
The concentration of the additive as a function of depth can be measured by nuclear reaction analysis. The data shown on the left demonstrates a significant surface excess above the bulk equilibrium concentration, confirming the extraordinary surface activity of the additive!
Contact angle measurements (below) with both water and dodecane show significant modification of the bulk surface properties with < 5% additive and surface saturation of the additive at about 10%. At this concentration contact angles with water of 110o are similar to PTFE. Furthermore, the difference between the data for annealed (red) and as spin coated (blue) is not large, again demonstrating very high surface activity. 10% by mass of additive equates approximately to a total concentration of fluorine atoms of 1% by mass!
The technology is very flexible and the additives could be easily decorated with other low surface energy groups such as silicon containing moieties. Alternatively, groups to render surfaces hydrophilic are also just as feasible.