(a) Sketch a short length of a polyacetylene molecule indicating the nature of the chemical bonds present. (b) Simple models of the electronic state in polyacetylene suggest that it should be a 1-dimensional metallic conductor. Explain why experimental measurements of the electrical properties of polyacetylene show that it is a semiconductor. (c) The electrical properties of semiconducting polymers are strongly influenced by chemical doping. (i) Describe the nature of a neutral soliton in a polyacetylene chain and explain how it can transport charge. (ii) Sketch a simple energy diagram showing the electron energy state of a neutral soliton relative to the HOMO and LUMO levels. (iii) Show how p-doping polyacetylene can lead to the formation of solitons