Synthesis of Heterograft Copolymers with a Semifluorinated Backbone by Combination of Grafting-through and Graftingfrom Polymerizations

Jeonghyeon Lee (1) , Gérald Lopez (2) , Bruno Ameduri (2) , Myungeun Seo (1)

1 KAIST - Korea Advanced Institute of Science and Technology
2 ICGM - Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier

We report that an alternating semifluorinated copolymer of chlorotrifluoroethylene (CTFE) and vinyl ether (VE) is an attractive platform for the synthesis of heterograft copolymers consisting of two distinct side chains. The radical terpolymerization of CTFE with PLA-tethered vinyl ether (PLAVE) synthesized by ring-opening polymerization and isobutyl vinyl ether (IBVE) as a spacer produced PLA-grafted fluorinated copolymer via a “grafting-through” manner. Two PLAVEs with different molar masses (2 and 10 kg mol–1) were successfully incorporated, and the grafting density could be controlled by varying the [PLAVE]/[IBVE] initial molar ratio. From the chlorine atoms in the CTFE repeating units, atom transfer radical polymerization (ATRP) of styrene was further employed to grow PS side chains following a “grafting-from” mechanism per each (CTFE-alt-VE) repeating unit dyad. First-order kinetics was observed for the styrene polymerization and supported controlled growth of PS. The resulting heterograft copolymers possessed regularly spaced PS chains and statistically distributed PLA chains on the backbone, generating a nanoscopic disordered morphology via microphase separation driven by incompatibility between PLA and PS. By copolymerization of styrene and divinylbenzene (DVB) in neat ATRP condition, a cross-linked polymer monolith with the disordered bicontinuous morphology could be also prepared via polymerization-induced microphase separation. The cross-linked precursor was converted into a mesoporous polymer with pore size of 3.7–10.4 nm by removal of PLA. The mesopore size was tunable by adjusting the PLA molar mass and styrene/DVB molar ratio.

Domaines: Polymères

Jeonghyeon Lee, Gérald Lopez, Bruno Ameduri, Myungeun Seo. Synthesis of Heterograft Copolymers with a Semifluorinated Backbone by Combination of Grafting-through and Graftingfrom Polymerizations. Macromolecules, 2020, 53 (8), pp.2811-2821. ⟨10.1021/acs.macromol.9b02493⟩. ⟨hal-03113228⟩