Projects for MChem or BSc Students 2012-13
These are possible projects in the Edler group this year - if there is something in a related area that you would like to work on, please come and talk to Dr Edler as many variations are possible!
Responsive Polymer Gels as Valves
This project, in collaboration with the Bristol Robotics Centre aims to make a valve for a biorobot which is driven by changes in pH or temperature rather than electricity. The biorobot uses bacteria to generate electricity for its operation but only in small amounts thus having valves which did not rely on electrical current to allow flow of nutrients etc to the bacterial chambers would allow the robot a longer operating time. In this project we will make valves from responsive polymers which swell or contract in response to chemical or temperature stimuli and study the relationship between the structure of the polymer gel and the amount of swelling/shrinkage in order to optimise the valve for this application. The amount of synthesis required can be varied according to your tastes (some of the polymers can be purchased, for direct use in making gels or we can synthesise tailored polymers for this purpose) Successful valves will be trialled in the robots at the Bristol Robotics Centre.

Block Copolymers to form Controllable Nanostructures
This project will involve synthesis of diblock copolymers either of two water-soluble polymers, one charged and one neutral in order to make switchable polymer micelles (which change their solublity as the pH changes eg as drug delivery agents or enzyme encapsulation). Alternatively copolymers could be prepared with one hydrophobic and one hydrophilic block. These will form micelles in aqueous systems and will be investigated for incorporation into responsive polymer films (eg for encapsulation of therapeutics in wound dressings). This project will be in collaboration with Dr Price and will enable you to learn common techniques for block copolymer synthesis, as well as techniques for nanostructure characterisation.

Calcium Effects on Polymer-Surfactant Interactions
Calcium is a ubiquitous ion, present in water supplies, rocks, and cruicial for biology. However it is also responsible for production of scale which causes major problems in industrial plants due to blocking of pipes. This project will look at calcium binding to micelles and water soluble polymers to try to understand the effects of the Ca2+ ion on their structure. We have found that Ca2+ enhances the interaction between zwitterionic molecules such as phospholipids with polymers enabling formation of nanostructured films and particles which do not form in the absence of calcium. This provides an interesting route to biocompatible nanomaterials and also a way to tune nanoscale structure in a very sensitive manner. This project does not involve synthesis, but will use a range of techniques to study calcium binding, micelle shapes and the interaction with polymers, including conductivity, surface tension and small angle X-ray scattering.

Porous Transition Metal Oxides
Transition metal oxide films are of enormous potential interest for a range of applications such as solar cells and in water splitting to make hydrogen. Giving these films a high surface area by making them porous increases the active surface available for reactions making them much more efficient, but nanoporous transition metal oxide films are tricky to prepare and a fool-proof route has yet to be developed. This project will use a variety of oxide precursors, in combination with surfactants and polymers to grow nanoporous films by dip coating. We will characterise the freshly prepared films using small angle X-ray scattering, spectroscopy and optical microscopy and test the stability of the films after the organic material has been removed to see if it is possible to make porous oxide films via this route.

Surfactant Chain Length Effects on Mixed Cationic-Anionic Micelles and Films
We have been studying the formation of nanostructured films using mixtures of cationic and anionic surfactants with water soluble polymers. So far we have only investigated one pair of cationic and anionic surfactants but it is known that the aggregation behaviour of surfactants depends strongly on the tail length. This project will study the effect of using different surfactant tail lengths on the structure of mixed micelles in solution and in the polymer-surfactant films. The solutions and films will be characterised using conductivity, TGA and small angle X-ray scattering.

To discuss any of these projects please contact Dr Edler and arrange a time to chat.