Electroactive composites based on polydimethylsiloxane and some new metal complexes

Abstract

Three different small molecule or polymeric well-determined complex structures containing siloxane moieties and 3d metals were incorporated into a polymeric matrix based on a polydimethylsiloxane of low molecular weight. After the incorporation of the complex, matrix crosslinking was performed with tetraethylorthosilicate, resulting in free-standing films. The films were investigated by scanning and transmission electron microscopy (SEM, TEM), dynamic vapour sorption (DVS) analysis, stress–strain measurements and dielectric spectroscopy. The presence of the siloxane moiety in the ligand (by its surface effect) improves the compatibility between the metal complex and the silicone matrix, which ensures good mechanical properties. Thus, modulus values between 0.10 and 0.50 MPa and elongations of 210–380% were obtained. Depending on the metal type and the complexation pattern, an increasing of the dielectric constant value up to 4.6 as compared with a value of 2.5 for the silicone matrix was obtained. The samples showed good electromechanical actuation behaviour even at small voltages.

The Current State of Silicone-Based Dielectric Elastomer Transducers

“…In addition to inorganic fillers, several complexes with various metals in silicone have been investigated for DET applications. As an example, iron, cobalt and titanium complexes were investigated by Cazacu et al, who discovered dielectric permittivities of up to ε′ = 4.7 with 3–5 wt% of the respective complexes. Also, copper‐phthalocyanine (CPO) complexes have been investigated due to their high dielectric permittivity (>10.000), with Zhang et al showing a dielectric permittivity of ε′ = 5.85 at 20 wt% CPO and improved actuation.…”

From Amorphous Silicones to Si-Containing Highly Ordered Polymers: Some Romanian Contributions in the Field

“…The resulted composites showed a slight decrease of elastic properties but an increase in dielectric permittivity of up to 100%, while the electromechanical sensitivity was almost double compared with the reference sample. Cu-, Co-, and Ni-atranes [ 98 ] or a 1D coordination polymer [ 99 ], were also tested as fillers for silicones. While in the latter case, a dielectric permittivity value of 4.6 was obtained at a load of 3 wt.% filler, regardless of the frequency, in the first case, remarkably high values were registered for dielectric permittivity but, unfortunately, also for dielectric loss, which makes these composites fall more into the semiconductor field.…”

Actuation Behavior of Multilayer Graphene Nanosheets/Polydimethylsiloxane Composite Films

“…The addition of a filler with high constant to the elastomer system is one of the most investigated solutions to this challenge. Inorganic particles (TiO 2 and titanates) [7,15], metals (iron, cobalt and titanium complexes) [16], organo-clays (montmorillonite) [17], as well as conductive fillers (carbon black, carbon nanotubes, and exfoliated graphite) [18,19] have been added in silicone matrix to investigate the actuator application. For the optimal system, a balance will have to be found between reinforcement and constant increase while not compromising the elastic modulus.…”