POLYPATT · Control and Application of Field Induced Polymer Patterns

Strong electric field gradients can produce forces that overcome the surface tension in a thin liquid polymer film to induce instabilities at the film surface. It is possible in this way to create structure in polymer films on a nanometre length scale. Understanding how the resultant patterns form has significant potential for improving nanodevice fabrication techniques but may also lead directly to the discovery of novel nanodevices. As part of the PATTERNs RTN, over 35 months the applicant has worked with some of the leading researchers in the thin film polymer instabilities field, and has been fully trained in the relevant experimental and theoretical methods. He has developed a new theoretical model that describes a polymer-air-polymer system under electric field and he has explored this system, not only theoretically but experimentally. The applicant has validated his theoretical model, and explored comprehensively the polymer type, thickness and viscosity parameter space of this system to provide new insights into the nucleation and spinodal processes responsible for the observed pattern formation. The experimental results are however from static measurements, and so detail of the dynamic instability formation process remains obscured. He proposes therefore to study the real-time formation of the polymer instabilities using a newly acquired optical 3-D topographic instrument modified for this purpose. In addition, the ambition of fabricating nanodevices based on these polymer instabilities requires an increased level of experimental control, and the coupling of these instabilities with nanoparticle inclusion for self-organisation into nanodevices (such as photonic crystals) is at the forefront of current research and still not well understood. He proposes therefore to develop new methods for controlling the experimental polymer instability system, and to use this control to allow fabrication and characterization of nanoparticle self-organised devices.