Defence A. Dianatdar Langeroudi: "Synthesis and Coating of Electroactive Polymers: Wet vs. Dry Processing"

Promotors: Prof. Francesco Picchioni, Prof. Ranjita Bose

Abstract: Electroactive polymers have been of the subject of great interest in recent decades due to their ability to show metal-like conductivity while retaining polymer-like flexibility at the same time. They have found broad applications in microelectronics, medicine and energy sectors, particularly where biocompatibility is involved. This is due to their soft and flexible nature, making them suited to human interface compared to their inorganic counterparts. Since these polymers are often used in the form of a thin coating layer on an underlying substrate, widespread research has been done on their synthesis and processing. In this regard, two different techniques have been developed simultaneously with and without the use of solvent for their processing. Each of these techniques have strengths and challenges related to the type of polymer, polymer film formation, film properties, substrate choice and interfacial phenomena. This thesis aims to first provide an overview of electroactive polymers and their processing techniques namely wet and dry routes. The merits and demerits of each route is discussed in detail based on the state-of-the-art literature. Their scientific progress and technological relevance has been critically compared. This thesis investigated each method to study different aspects of these polymers. In particular, an electroactive unit (triphenylamine) was chosen as the building block for design and synthesis of different polymer architectures and how it affects their electrochemical energy storage performance. These polymers were investigated using wet processing, since their dry processing would be extremely challenging. In the second part of this thesis, the dry processing technique of oxidative chemical vapor deposition (oCVD) is comprehensively discussed from the early works which were less than two decades ago up to its current state-of-the-art. A unique contribution of this thesis is the synthesis of polypyrrole using oCVD with an in-depth molecular characterization to gain insight into its processing condition and thin film properties. The application for conductive coatings of polypyrrole was studied in the context of electrochemical energy storage and piezoresistive sensing devices using porous or delicate substrates.

Dissertation