Electrochemical loading of TEM grids used for the study of potential dependent morphology of polyaniline nanofibres

Summary An electrochemical method for loading electroactive materials over the TEM grid is reported. The protocol has been demonstrated using polyaniline as an example. The electroactive polymer was directly deposited over the Au TEM grid, used as working electrode in a 3 electrode electrochemical cell. The undisturbed as‐deposited morphologies under the influence of various counter ions and ex situ electrochemical states have been studied and compared. Contrary to behaviour in bulk the individual polyaniline fibre was found thinner at anodic potentials. The movement of counter ions as a function of the electrochemical state of the polymer was studied using STEM‐EDX elemental mapping. Lay description Most crucial step in any electron microscopy is sample preparation. Although it was impossible to transfer an electroactive material deposited on an electrode to the grid with its native morphologies. Therefore a general method has been devised to load electroactive material directly over the TEM grid. The Au TEM grid was used as working electrode in a purpose designed three electrode electrochemical cell and the undisturbed as‐deposited morphologies has been studied.