Neutron reflectometry studies of conducting polymer films

Within the field of conducting polymers, it is well understood that the variables in film formation, ranging from the polymerisation and deposition methodologies to the supporting electrolyte in the deposition solution, can produce a wide range of different electrochemical and structural properties for a given polymeric species. For the most part, studies into these effects rely on spectroscopic, electrochemical and surface characterisation techniques. In this work, neutron reflectometry is used to identify the extent of solvent content and spatial distribution within polymer films, providing insight into the internal structure. In conjunction with electrochemical methods, two types of variables are explored: the addition of carbon composites and the electrochemical control function used for polymerisation/deposition. The effect of the incorporation of carbon nanoparticles is explored in the case of composite poly(3,4-ethylenedioxythiophene)-nanodiamond films. These are revealed to be similarly electroactive to pristine poly(3,4-ethylenedioxythiophene) films but present a more ordered internal structure. The effect of the electrodeposition method is investigated by comparing films produced by potentiodynamic, potentiostatic and galvanostatic deposition in the case of two different polymers, polypyrrole and poly(3,4-ethylenedioxythiophene). The results show that the polymerisation efficiency for a given growth protocol differs depending on the polymer species, as do the structural variations, such as porosity or structural stability following charge/discharge processes