A study of microporous polymeric materials for electronic applications

Heasman, Patrick and Trewin, Abbie and Hoster, Harry (2020) A study of microporous polymeric materials for electronic applications. PhD thesis, Lancaster University.

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Abstract

In this thesis we look at two microporous polymer materials and their respective electronic properties. We firstly assess the electronic properties of pyrene-based conjugated microporous polymers (CMPs). The research revolves around the hypothesis that unique structures, called here ”molecular rings”, are the influencing factor of their luminescent properties. Here we showed that the introduction of a linear co-monomer greatly reduced the number of molecular rings observed in a pyrene-based CMP (S0). With this in mind, we designed two further materials, S1 and S2, that use non-linear comonomers (1,3-ibromobenezene and 1,2-dibromobenzene, respectively). These were computationally generated and subsequently synthesised. The rationalisation of the co-polymeric CMPs S1 and S2 demonstrated a rapid increase in molecular rings. The synthesised CMPs showed luminescence consistent with our computational predictions. Further investigation into the formation mechanism of these materials has led to an ”inference” technique that could be utilised for a qualitative assessment of the incorporation of monomers, and their electronic properties. The second set of materials studied the diffusive behaviour of the newly introduced OSPC-1 material as an anode for lithium ion batteries, and also as anodes for alternate ion batteries (sodium, potassium, magnesium, and calcium). We have also predicted a novel set of materials to expand upon the OSPC family. OSPC-0 introduces a carbon framework with reduced sp3-sp3 node distances, whereas OSPC-2 and OSPC3 have increasing sp3-sp3 node distances (node-to-node distance: OSPC-0 < OSPC-1 < OSPC-2 < OSPC-3). Overall, the active diffusion rate of lithium ions increased with an increase of node-to-node distance. However, the trend established for the ions is more complex, with the active diffusion rate being determined by a combination of ionic radius and node-to-node distance.