Abstract: A material comprising crosslinked polyrotaxanes which exhibits desired viscoelasticity, particularly stress-strain characteristics with a wide low-stress region, in spite of being free from solvent; and a process for production of the same. The material comprises a first polyrotaxane bearing first cyclic molecules and a second polyrotaxane bearing second cyclic molecules, and the first and second polyrotaxanes are crosslinked via the first and second cyclic molecules. The material is free from solvent and exhibits a stress of 2.0 MPa or below at 50% strain.

Abstract: A material comprising crosslinked polyrotaxanes which exhibits desired viscoelasticity, particularly stress-strain characteristics with a wide low-stress region, in spite of being free from solvent; and a process for production of the same. The material comprises a first polyrotaxane bearing first cyclic molecules and a second polyrotaxane bearing second cyclic molecules, and the first and second polyrotaxanes are crosslinked via the first and second cyclic molecules. The material is free from solvent and exhibits a stress of 2.0 MPa or below at 50% strain.

Abstract: A material comprising crosslinked polyrotaxanes which exhibits desired viscoelasticity, particularly stress-strain characteristics with a wide low-stress region, in spite of being free from solvent; and a process for production of the same. The material comprises a first polyrotaxane bearing first cyclic molecules and a second polyrotaxane bearing second cyclic molecules, and the first and second polyrotaxanes are crosslinked via the first and second cyclic molecules. The material is free from solvent and exhibits a stress of 2.0 MPa or below at 50% strain.

Abstract: A material comprising crosslinked polyrotaxanes which exhibits desired viscoelasticity, particularly stress-strain characteristics with a wide low-stress region, in spite of being free from solvent; and a process for production of the same. The material comprises a first polyrotaxane bearing first cyclic molecules and a second polyrotaxane bearing second cyclic molecules, and the first and second polyrotaxanes are crosslinked via the first and second cyclic molecules. The material is free from solvent and exhibits a stress of 2.0 MPa or below at 50% strain.

Abstract: An actuator includes a spirally rolled cylindrical sheet body. The sheet body is formed by attaching an electrode on each side of a dielectric elastomer layer. When a voltage is applied to the electrodes, the sheet body is contracted along the direction of its thickness, and expanded in directions perpendicular to its thickness. The actuator is actuated by applying a voltage to the electrodes and stopping the voltage application, so that the cylindrical sheet body is extended and contracted along the direction of the axis. The material forming the dielectric elastomer layer has a low strain region, where the value of a strain based on a stress acting on the dielectric elastomer layer varies from zero to a value that is greater than and close to zero, and a high strain region, where the value of the strain is greater than that in the low strain region. The Young's modulus in the low strain region is less than the Young's modulus in the high strain region.

Abstract: An actuator includes a spirally rolled cylindrical sheet body. The sheet body is formed by attaching an electrode on each side of a dielectric elastomer layer. When a voltage is applied to the electrodes, the sheet body is contracted along the direction of its thickness, and expanded in directions perpendicular to its thickness. The actuator is actuated by applying a voltage to the electrodes and stopping the voltage application, so that the cylindrical sheet body is extended and contracted along the direction of the axis. The material forming the dielectric elastomer layer has a low strain region, where the value of a strain based on a stress acting on the dielectric elastomer layer varies from zero to a value that is greater than and close to zero, and a high strain region, where the value of the strain is greater than that in the low strain region. The Young's modulus in the low strain region is less than the Young's modulus in the high strain region.