Ferroelectric nanocomposites of polyvinylidene fluoride/polymethyl methacrylate blend and BaTiO3 particles: Fabrication of β-crystal polymorph rich matrix through mechanical activation of the filler

Abstract

Nanocomposites of polyvinylidene fluoride/polymethyl methacrylate (PVDF/PMMA) blend and mechanically activated barium titanate (BaTiO3) particles were prepared by melt mixing. Modification of filler by means of mechanical activation has a profound effect on the crystallization of PVDF in the blend matrix. Raman analysis showed that the modified BaTiO3 particles, due to higher specific surfaces, induce, predominantly, the crystallization of the electrically active β-phase of PVDF, while the initial micron size particles induce the formation of the most common but non-polar α-crystal form. The introduction of activated particles reduces the overall crystallinity but slightly affects the crystallization and melting temperatures of the matrix. Dielectric spectroscopy revealed that at fixed filler content the dielectric constant of the blend increases with decreasing of the particle size (increasing of the activation time). A similar trend was observed for the storage moduli in dynamic mechanical analysis; the stiffness of the composite was higher when mechanically activated particles were used.

Comparison of PVDF/MWNT, PMMA/MWNT, and PVDF/PMMA/MWNT nanocomposites: MWNT dispersibility and thermal and rheological properties

“…To date, only a few studies on PVDF/PMMA blend-based nanocomposites have been reported [19][20][21][22][23].…”

“…Mofokeng et al [19] used activated BaTiO 3 as filler to prepare PVDF/PMMA blendbased nanocomposites. The presence of activated BaTiO 3 induced β-form PVDF crystals and improved the stiffness.…”

Fillers in advanced nanocomposites for energy harvesting

“…The first technique that considerably influences the amount of the b-crystalline phase is in the different preparation step, such as the blending of PVDF with PMMA (Mokofeng et al, 2014) or copolymerization of PVDF with trifluoroethylene. Many studies have reported that the b-crystalline phase is responsible for the piezoelectric properties of PVDF.…”

Fabrication and characterization of β-poly(vinylidene fluoride)/silane-treated titanium dioxide dielectric nano-composites

“…Alternatively, high piezoelectric constant inorganic materials are often used as secondary phase fillers to improve the piezoelectric performance. Examples of ceramic based materials are lead zirconium titanate (PZT) [14] and barium titanate (BaTiO 3 ) [11,[15][16][17] while carbon based materials such as multi-walled carbon nanotubes (MWCNT) [18,19], single-walled carbon nanotubes (SWCNT)/carbon fullerenes (C60) [20], and graphene oxides (GO) [21] can also be used. Despite these composites' high performance, most of these additives are brittle, expensive, and difficult to process.…”