PCAT and the Kittens: Design and synthesis of water processable conjugated polymers and monomers for sustainable hybrid materials
About this ebook
The polar polythiophene PCAT was obtained by introducing a carboxylate functional group to the CP sidechain, giving pH-tunable water solubility and processability. PCAT could be fixated onto and recovered from Lyocell cellulose thread substrates with simple acid-base chemistry. Acid-mediated oxygen doping was used to obtain electrically conducting CP:cellulose threads. The doping resulted in loss of recoverability of the CP due to hydrogen peroxide triggered formation of covalent bonds. A potassium iodide-based strategy for preventing unwanted crosslinking resulted in stable, conductive, and removable electroactive coatings on cellulose threads, using water as the sole solvent.
The scope of the oxa-Michael addition for sidechain functionalization was explored as a way of achieving new CP-functionalities. Based on the chemical design of the CAT-monomer, 5 monomer derivatives were synthesized using neat oxa-Michael addition reactions optimized via small scale screening. Carboxylate, amide and phosphonate functionality were all successfully installed via oxa-Michael addition at moderate to excellent yields.
In a final project, synthesis of water-soluble conjugated monomers allowed development of a fully water based direct arylation polymerization protocol. Simple thiophene and thienothiophene based polymers were synthesized by using water-soluble monomers and benign additives for catalyst solubility.
In summary, this work has advanced the knowledge of water-processable polar polythiophenes and their function and challenges as removable electroactive cellulose coatings. Further, oxa-Michael addition has been proven as a versatile way to synthesize functionalized glycolated thiophene monomers and a promising direct arylation polymerization strategy in water (WaDAP) has been developed.
