Synthesis and characterization of composite shear thickening fluids (STFs) containing carbon nanofillers are presented. Shear thickening fluids have attracted particular scientific and technological interest due to their unique ability to abruptly increase viscosity in the case of a sudden impact. The fluids have been developed as a potential component of products with high energy absorbing efficiency. This study reports on the rheological behavior, stability, and microstructure of the STFs modified with the following carbon nanofillers: multi-walled carbon nanotubes, reduced graphene oxide, graphene oxide, and carbon black. In the current experiment, the basic STF was made as a suspension of silica particles with a diameter of 500 nm in polypropylene glycol and with a molar mass of 2000 g/mol. The STF was modified with carbon nanofillers in the following proportions: 0.05, 0.15, and 0.25 vol.%. The addition of the carbon nanofillers modified the rheological behavior and impact absorption ability; for the STF containing 0.25 vol.% of carbon nanotubes, an increase of force absorption up to 12% was observed.

In this article, the novel type of dielectric elastomer made of polydimethylsiloxane, multi-walled carbon nanotubes, and carbon grease is presented. The aim of the study was the development of compliant electrodes with ability for large deformation under applied voltage. The largest deformation of 47% was obtained for electrodes made of 2 wt% of multi-walled carbon nanotubes and 20 wt% of carbon grease. Electrical conductivity achieved for this material was 4.8 S/m. Good dispersion of conductive fillers within silicone matrix was obtained by calendaring technique. It was found that electrical percolation threshold for the compound was below 0.05 wt%. The structure of the material and its mechanical properties were determined. It was described that both properties, electrical conductivity and stiffness of the nanocomposite, have a significant influence on the extent of the electrode deformation. Two actuator designs are presented as the examples of application of developed material.

Rheological behavior and structural stability of shear thickening fluids (STFs) based on amorphous silica KE-P50 (500 nm) and polypropylene glycol, with molar mass 2000 g/mol, were studied. The static and dynamic rheological measurements were performed using rheometer ARES and stability tests were carried out using the Turbiscan LAB. The preliminary tests were performed for the STFs having 50-55 vol.% of silica and the detailed studies were carried out for two fluids, with 50 and 53 vol.% of silica, respectively. All the STFs studied exhibit shear thickening properties. Both, the initial and maximal viscosities increase with growing of silica content. For the shear rates studied the viscous component of the shear modulus dominates over the elastic one. The Turbiscan tests showed that both the suspensions studied exhibit excellent stability over the 8 days of the test. The synthesized STFs can be used as a component of flexible energy absorbing and protecting structures.