Poly(vinylidene fluoride)/Polymethylene-Based Block Copolymers and Terpolymers

Abstract

Dual crystalline diblock copolymers consisting of polymethylene (PM) and poly(vinylidene fluoride) (PVDF) blocks as well as triblock terpolymers with polystyrene (PS) as middle block were synthesized. For the synthesis, two/three different polymerization methods such as polyhomologation, atom transfer radical polymerization (ATRP) and iodine transfer polymerization (ITP) along with chain-end post-polymerization reactions were employed. Solid-state NMR spectroscopy revealed the characteristic peaks of all constituent blocks while gel permeation chromatography (GPC) results demonstrated the controlling/living nature of all implemented polymerization methods. The analysis of crystallization behavior based on differential scanning calorimetry (DSC) indicates the presence of different PVDF crystalline phases (α, β, and γ) upon the incorporation of PM and PS blocks. Further analysis with X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopies revealed the co-existence of α-and β-phases in diblock and βand γ-phases in triblock terpolymer. An initial study on self-assembly in DMF, a selective solvent for PVDF and PS, was performed by dynamic light scattering (DLS) and atomic force microscopy (AFM). electroactive β-phase but also non electroactive α-phase for the diblock copolymer while β-and γphase for triblock terpolymers. Furthermore, according to DSC, XRD and IR results, the presence of a PS intermediate block between PM and PVDF led to the formation of mainly γ-phase. Efforts to extend the synthesis of a variety of semi-fluorinated polymers, as well as to gain additional insights into their morphology, self-assembly, and dispersive properties are currently underway in our laboratory. These type of PVDF-based copolymer could be potentially used as polymer binders for lithium-ion batteries optimizing properties like adhesion strength and flexibility. Finally, this study opens new horizons towards the synthesis of PM-b-PVDF-based complex macromolecular architectures.

Iodine‐transfer polymerization and CuAAC “click” chemistry: A versatile approach toward poly(vinylidene fluoride)‐based amphiphilic triblock terpolymers

“…) revealing the melting points of PVDF and PEO ( T m = 160–175 and 39 °C, respectively) and PS glass transition temperature ( T g = 98 °C), demonstrates the three blocks are separated from each other and behave as phase‐separated domains. Due to polymorphic crystallization of PVDF, two different melting points are observed in the case od di‐ and triblocks …”

“…Due to polymorphic crystallization of PVDF, two different melting points are observed in the case od di-and triblocks. 18 The higher melting temperature of PVDF in triblock terpolymers than the corresponding diblock copolymers (Fig. 6) is due to the presence of β + γ-phases in terpolymers as compared to α + β-phases in copolymers.…”

“…Under this consideration, it would be interesting to study the influence of the covalently linked partner in PVDF‐based block copolymers (BCPs) and triblock terpolymers (nm scale) on the PVDF crystalline phase. A few papers toward this direction appeared in the literature in BCPs of PVDF with amorphous and crystalline partners …”

“…A few papers toward this direction appeared in the literature in BCPs of PVDF with amorphous and crystalline partners. 14,[18][19][20] Until now, the number of reports on PVDF-based BCPs is limited. Three main strategies involving degenerative chain transfer such as macromolecular design via the interchange of xanthates, reversible addition-fragmentation chain-transfer polymerization, 4,[21][22][23][24][25] and iodine-transfer radical polymerization (ITP) [26][27][28][29][30][31] have been applied for the synthesis of PVDF BCPs.…”

“…The vital steps of this methodology are the synthesis of azideterminated PVDF BCPs and alkyne-terminated hydrophilic polymer, which are subsequently used for "click" reaction. We first prepared PVDF-b-PS-I diblock copolymers via ITP (Scheme 1) and converted into PVDF-b-PS-N 3 by reaction with sodium azide 18,21 and then "clicked" with alkyne-terminated PEO to produce amphiphilic PVDF-b-PS-b-PEO triblock terpolymers (Scheme 1). Furthermore, the self-assemblies in films and organic solvents or water, the thermal properties, the crystalline phases of PVDF, and the carrier ability of the terpolymers were reported.…”