| Summary: | Polydimethylsiloxane (PDMS) elastomers are attractive for soft actuation but their intrinsically low permittivity demands high electric fields and promotes premature electrical failure. To address this limitation, this study implements a Synergistic Layer System (SLS) in which a hard filler (TiO2) and soft fillers (high-permittivity silicone oil (HPSO) and glycerol (Gly)) are co-embedded in PDMS to raise dielectric response while moderating stiffness. A commercial PDMS A/B (1:1) pre-blend was formulated as single-filler films (TiO2, HPSO, Gly; 15 wt%) and SLS hybrids (TiO2 + Gly and TiO2 + HPSO; 1:1, total 15 wt%), then degassed, cast in glass Petri dishes, and oven-cured at 80 °C (~ 40–80 µm). Mechanical properties (Young’s modulus, tensile strength, elongation at break) were obtained by quasi-static uniaxial tensile testing on a universal testing machine. Breakdown strength followed IEC 60243-1/-2 using a step-up high-voltage setup with semi-spherical electrodes. Relative permittivity (Er) was measured on an impedance analyzer (20 Hz – 30 MHz) using carbon-grease circular electrodes. Relative to pure PDMS, single-filler films improved either dielectric response or compliance but introduced clear trade-offs. In contrast, the SLS hybrids delivered balanced gains- TiO2 + Gly increased Er while tempering stiffness and TiO2 + HPSO provided the most balanced combination of Er, modulus, and breakdown strength. These results show that co-embedding a hard filler with a soft filler in a single layer complements interfacial polarization and plasticization, enabling higher-performance PDMS actuators without excessive stiffness.
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