Absolute molecular weight of polyaniline and synthesis of polyaniline-co-poly-2-methylaniline block copolymer

The absolute molecular weight of polyaniline in the pernigraniline, emeraldine, and leucoemeraldine oxidation states has been measured by light scattering and the exact number of aniline repeat units determined for the first time. Using potential-time profiling to monitor the chemical oxidative polymerization of aniline using ammonium peroxydisulfate oxidant, all three oxidation states of polyaniline can be synthesized in one step and the evolution of polymer molecular weight monitored. The pernigraniline intermediate formed during the chemical oxidative polymerization of aniline increases by 17--20% when it is converted to emeraldine, which is consistent with a two-step aniline polymerization mechanism. These findings establish a solid experimental framework to chemically synthesize block copolymers of polyaniline by using different monomers to intercept the reaction at the pernigraniline oxidation state. Polyaniline-co-poly-2-methylaniline block copolymer was successfully synthesized using this approach for the first time.*;* This study has been published in the Journal of the American Chemical Society. Sumedh Surwade is the second author on this paper and has done all the experimental synthesis work and part of instrumental and characterization work. Contributions of the other authors are as follows: Harsha Kolla---Instrumental and part of characterization work; Xinyu Zhang---Experimental design and helpful discussion; Alan G. MacDiarmid---helpful discussions; Sajeev Manohar---Overall experimental design and advice. ** Major contents of the Theory section of this thesis has been included from Wyatt technology lecture materials notes with permission from Wyatt Technology Inc.