Self-sensing magnetic actuator based on sustainable collagen hybrid nanocomposites.

Taking into account that natural polymers are renewable and biodegradable, hybrid materials based on natural polymers are required for advanced technological applications with reduced environmental footprint. In this work, sustainable composites have been developed based on collagen as a polymeric matrix and different magnetic fillers, in order to tailor magnetic response. The composites were prepared by solution casting with 30 wt% of magnetite nanoparticles (FeO NPs), magnetite nanorods (FeO NRs) or cobalt ferrite nanoparticles (CoFeO NPs). It is shown that the magnetic filler type has no bearing on the morphology, physical-chemical, or thermal characteristics of the composites, whereas the mechanical properties are determined by the magnetic filler, leading to a reduction in tensile strength, with values of 4.95 MPa for FeO NPs, 9.20 MPa for FeO NRs and 5.21 MPa for CoFeO NPs containing samples. However, the highest magnetization saturation is obtained for FeO NPs (44 emu.g) and the higher coercive field for CoFeO NPs (2062 Oe). In order to prove functionality of the developed composites, a self-sensing magnetic actuator device has been developed with the composite film with CoFeO NPs, showing high stability over cycling.