Proton exchange membranes based on columnar side-chain liquid crystalline polyethers and polyamines

Identifier:  TDX:2427

Handle: https://hdl.handle.net/20.500.11797/TDX2427

Authors:  Montané Montané, Xavier

Abstract:
In research, scientists try to extract guiding principles from nature in order to provide technological devices which allow us to live in a more sustainable society. During the last decades, one natural phenomenon that has been studied extensively is proton transport. Proton transport in natural systems occurs with high selectivity and efficiency like in the photosynthesis of green plants. For this reason, most research in the field of proton conductivity has been devoted to the development of new proton-conducting materials to be used in electrochemical cells. To mimic this behaviour, we design materials containing ion transport channels by self-assembling, in which the channels localise the permeation path and simultaneously protect the transport process against the environment. Our studies are focused on the synthesis of liquid-crystalline polymers which subsequently were employed to obtain membranes that can be used in proton transport systems. The synthesised liquid-crystalline polymers have to present a suitable structure to be used in proton transport systems. Hence, we chemically modify polyamines [poly-2-(aziridin-1-yl)-ethanol] and polyethers (linear polyglycidol) with a tapered dendron at different extent. Once grafted to the polymers, the dendrons confer to them liquid-crystalline behaviour. The resulting copolymers self-assemble into a columnar structure, due to an exo-recognition of the side-chain dendrons. Thus, the inner polymer chain could work as an ion channel. Afterwards, the preparation of oriented membranes based on these polymeric materials were carried out. Finally, these membrane are assessed as far as their proton conductive properties are concerned.