Poly(3,4-ethylenedioxythiophene) (PEDOT) has established itself as the conducting polymer of choice for bioengineering applications in recent years owing to its excellent stability, biocompatibility, and exceptional conductivity. Though extraordinary, several drawbacks still limit its full potential in biological systems, including sub-optimal mechanical properties, bioactivity and degradation. In this thesis, PEDOT is taken back to the drawing board to design and synthesise innovative new derivatives and increase its utility in biomedicine still further.
In the first half of the thesis, conventional covalent polymer derivatives are explored. In Chapter 2 the problem of degradation is approached, and a range of design options presented and characterised. Chapter 3 outlines the synthetic derivations that have been pursued in adding functionality to PEDOT-based backbones. This should allow for its use in a number of new avenues of biomaterials such as organic electrochemical transistors and 3D printing.
The latter half addresses supramolecular systems. In Chapter 4 the monomeric form, 3,4-ethylenedioxythiophene (EDOT), is incorporated into a self-assembling hydrogel system with full characterisation and elucidation of structure-property relationships. Chapter 5 moves to look at a quite different self-assembling system. A related polymer poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT) decorated with poly(ethylene glycol) (PEG) chains is shown to assemble into unprecedented fractal structures. The dependence of such structures on assembly conditions and PEG chain length is explored and mechanisms proposed with the aid of simulations.