Table 1.

Comparison of natural muscle and spider silk to different polymeric-based synthetic biomimetic muscle materials

Muscle fiberSilk fiberPolyurethane (electrostrictive)Liquid crystal polymersConductive polymersFerroelectric polymers
Sustainable stress (MPa)0.1-0.35801.90.455–3420
Work density (kJ m–3)8 (typical)–40 (max)5001003-56100300
Power density (W kg–1)50–300130–190*1150 (max)
Strain (%)20,> 402.51119–452–123.5
Modulus (MPa)10–6018000174800400
MechanismChemicalHumidityVoltageVoltageVoltageVoltage
  • * Power density was calculated using both 3 and 2 s response times

  • Madden et al., 2004

  • Kornbluh et al., 1998