Carbon fiber reinforced polymer (CFRP) composites are widely used in high-performance applications like commercial aircraft, military aircraft, turbines, automobile and sports industries due to its high specific strength, stiffness and corrosion resistance. In CFRP composites, fibers are encapsulating with insulating polymer results into low thermal, electrical and shielding properties which limit their use. Therefore, multifunctional composites are necessary to develop so that CFRP can have better electrical and thermal properties along with mechanical properties. To develop even better composite materials carbon nanotubes (CNTs) have been grown directly on the surface of carbon fibers using chemical vapor deposition (CVD) technique. Mechanical testing on single fiber composites as well as laminated composites are carried out to evaluate the effect of synthesized nanotubes on the interfacial strength, wettability, bending response, tensile response, interlaminar strength, and fracture strength of CFRPs.

The average properties of a polymer composite depends on the size and properties of the interface/interphase region in the vicinity of the reinforcing filler. Hybrid composite having partly concentrated and partly dispersed interphase region. The incorporation of CNTs significantly changes the size and properties of interphase, and also affects the interfacial chemistry and microstructure in multiscale and hybrid composites while transition is also gradual in an interphase region of finite thickness in CNT reinforced CFRPs as compared to conventional CFRPs. Thus, the presence of an interphase region eliminates stress concentration around the filler material. 

Soft actuator materials change their shape or size in response to stimuli like electricity, heat, light, chemical or pH. These actuator materials are compliant and well suited for soft mechatronics and robots