Syntheses and morphologies of fluorinated diblock copolymer prepared via RAFT polymerization

• BCPs of PMMA and PHFBA were prepared via RAFT polymerization.
• The BCPs had controlled molecular weight with narrow PDI.
• TEM showed that the BCP had phase separated morphology with lamellar stacking.
• Morphology of BCP can be tuned by using a mixture of solvents, THF and MEK.

Block copolymers (BCPs) consisting of fluorinated and non-fluorinated blocks can show interesting morphology, because of the presence of two dissimilar blocks. In this investigation BCPs of methyl methacrylate (MMA) and 2,2,3,3,4,4,4-heptafluorobutyl acrylate) (HFBA), (PMMA-b-PHFBA) were synthesized via reversible addition fragmentation chain-transfer (RAFT) polymerization using 2-cyano-2-propyl dithiobenzoate (CPBT) as chain transfer agent (CTA). Gel permeation chromatography (GPC) and 1H NMR analyses confirmed the synthesis of well-defined BCP. TEM and XRD analyses showed lamellar stacking in the BCP. Surface morphology and topography of the BCP were analyzed by SEM and AFM analyses. The morphology of the BCP in THF and methyl ethyl ketone (MEK) solvent mixture was studied by TEM analysis. Morphology of the BCP varied from lamellar to spherical micelles with the variation of THF-MEK ratio in the solution, as evidenced by TEM and DLS analyses.

PMMA-b-PHFBA was prepared via RAFT polymerization and its morphology in bulk and in solution was studied.Morphology transition of PMMA-b-PHFBA from stacked lamella to micelles with the variation in THF and MEK solvent ratio; A (THF:MEK = 5:0), B (THF:MEK = 4:1), C (THF:MEK = 3:2), D (THF:MEK = 1:4), E (THF:MEK = 0:5).Figure optionsDownload as PowerPoint slide