Role of Nanoparticle Surface Charge on the Nucleation of the Electroactive β-Poly(vinylidene fluoride) Nanocomposites for Sensor and Actuator Applications

Abstract

The electroactive β-phase of poly(vinylidene fluoride) (PVDF) can be nucleated by introducing CoFe 2 O 4 nanoparticles within the polymer matrix, leading to electroactive materials with large potential for sensor and actuator applications. The effects of the CoFe 2 O 4 nanoparticle electrostatic charge on the phase crystallization of PVDF polymer is reported. For this purpose, CoFe 2 O 4 nanoparticles were coated with anionic (SDS), nonanionic (Triton X-100), and cationic (CTAB) surfactants, and the obtained coated nanoparticles were used as fillers. It is found that the piezoelectric β-form of the polymer increases when CoFe 2 O 4 nanoparticles with higher negative electrostatic charge are added. This behavior is attributed to the interaction between the negatively charged magnetic particles and the polymer CH 2 groups, having a positive charge density. Further the relationship between the β-phase content and the piezoelectric response has been demonstrated. The magnetostriction of the ferrite nanoparticles and the proven piezoelectricity of the polymer allows the use of the material in piezoelectric and magnetoelectric sensors or/and actuators.

Effect of Cobalt Ferrite Loading on Differential Scanning Calorimetry of Magnetic Polymer Composites

“…Moreover, thermal properties [6,8] observed were not consistent to ours even when the interactions between magnetic particles and polar PU chains are provided. In fact, the interactions between CoFe 2 O 4 particles of order of 100 nm and polar functional groups on PU chains are expectedly weaker than the electrostatic interactions which occurred in the case of surface-modified CoFe 2 O 4 nanoparticles and electroactive PVDF [7]. This weak interaction, as a result, might not be enough to nucleate regular order PU chains.…”

“…Interfacial interactions between magnetic fillers and polymeric matrices strongly influence thermal properties, stability and degradation of magnetic polymer composites [6][7][8]. The geometrical factor is critical as the nanoscale fillers increase the interfacial area.…”

“…From the thermal gravimetry analysis, the suitable loading of ferrite nanoparticles into polyvinylidene fluoride (PVDF) introduced the formation of crystallinity due to the interfacial interaction between nanoscale ferrites and PVDF chains [6]. The degree of crystallinity in this polymer matrix as well as the electrostatic charge on particles were increased with the levels of ferrite loading [6,7]. CoFe 2 O 4 , in particular, whose surface charge could be modified by coating surfactants promoted the nucleation of piezoelectric b phase making PVDF/CoFe 2 O 4 composites a suitable choice for magnetoelectric transducers and sensors [7].…”

“…The degree of crystallinity in this polymer matrix as well as the electrostatic charge on particles were increased with the levels of ferrite loading [6,7]. CoFe 2 O 4 , in particular, whose surface charge could be modified by coating surfactants promoted the nucleation of piezoelectric b phase making PVDF/CoFe 2 O 4 composites a suitable choice for magnetoelectric transducers and sensors [7]. Differential scanning calorimetry (DSC) was also used to compare the loading effect of CoFe 2 O 4 with nickel ferrite (NiFe 2 O 4 ) on the crystallization of PVDF [8].…”

Influence of MWCNTs on β-Phase PVDF and Triboelectric Properties

“…In addition, triboelectric performance can be enhanced by regulating the surface morphology. Regarding the PVDF composites, multiwalled carbon nanotubes (MWCNTs) in PVDF composites can produce inductive charges on the surface during electrospinning, wherein the -phase of PVDF crystallizes on the surface of the MWCNTs, resulting in the transformation of local amorphous regions into the -phase crystalline structures [11,15,16].…”