Columnar liquid-crystalline polymers containing Nitrogen at the backbone to be used to prepare ion-transport membranes

Identificador:  TDX:4449

Handle: https://hdl.handle.net/20.500.11797/TDX4449

Autors:  Guardià Blanch, Jordi

Resum:
Climate change, global warming, greenhouse gas emissions are some of the problems that our generation has to face and solve. Pursuing a solution to these challenges, fuel cell technologies and, in particular, polymer electrolyte membrane fuel cells have emerged as alternatives to fossil fuels. Side chain liquid crystalline polymers present unique characteristics such as self-assembly that make them promising candidates for the development of proton conducting membranes. In this work we present the synthesis and characterization of dendronized poly(2-oxazoline)s, as well as their monomer precursor. Hybrid membranes were prepared with these new poly(2-oxazoline)s using a polyester fabric as a support. These membranes were widely characterized, and transport studies were carried out using different techniques, such as linear sweep voltammetry, electrochemical impedance spectroscopy and permeability tests. The findings observed during these investigations reported the potential use of these membranes for fuel cell applications, which relies on their outstanding proton selectivity. At the second part of this thesis, we design bio-based wood supports. Delignified wood present unique characteristics that has allowed the formation of new bio-based composite materials. Taking advantage of the natural hierarchical organization of wood pores, it is possible to use these wooden discs as supports for the preparation of hybrid proton-conducting liquid crystalline membranes by the infiltration of a dendronized polyether inside the pores of the support. Therefore, an in-depth study that involved the preparation, optimization, and characterization of delignified and functionalized wood discs was carried out. Besides, hybrid membranes assembled with these two supports were characterized and their ion transport properties were investigated, revealing that these membranes had excellent proton selectivity.