Random networks comprised of millimeter-long multi-walled carbon nanotubes (CNTs) have shown unique microstructure change mechanisms under uniaxial strain. These networks can be modified into highly aligned microstructures from strain-induced plastic deformation. Applying a treatment consisting of an uncured resin as a load transfer enhancement medium leads to a dramatically increased degree of alignment and final mechanical properties of the CNT networks. The structural evolution of the CNT networks includes different modes: de-bundling, elongation to reduce waviness, sliding friction, and packing for self-assembly into large bundles. The high ductility of the treated networks, which allows the network to achieve high degrees of strain-induced alignment is mainly because the extra high aspect ratios of the individual CNTand their bundles as well as enhanced load transfer. High aspect ratio causes high degrees of entanglement and locking points between the nanotubes in the random network, which are critical to provide adequate nanotube to nanotube load transfer for ductile deformation and lead to substantially increased CNT alignment during mechanical stretching. The classical strain strengthening mechanisms used in metals and polymers such as strain hardening and crystallization of long molecular chains are discussed and compared to CNT network deformation mechanisms. The CNT network strain hardening parameter n value is as high as 0.65, over three times that of annealed low-carbon steel and more than four times of polycarbonate plastics. Strength coefficient K values for the CNT network also show high values up to roughly 450 MPa, comparable to that of annealed magnesium alloys. The results show how the high degree of alignment of CNT networks and strain strengthening can be achieved through simple uniaxial strain and load transfer medium.

In this research, networks of single-walled carbon nanotubes (SWNTs) were used to host activated carbon (aC) microparticles to fabricate freestanding composite electrodes without the use of polymer binders. The aC-SWNT composite electrodes with up to 50 wt. % aC showed specific surface areas approaching 1000 m 2 /g and electrical conductivities >36 S/cm. The composite electrodes possessed the properties of both pure SWNT electrodes (e.g. low ohmic drop and rapid ion diffusion) and activated carbon particles (e.g. high specific capacitance). With an interconnected mesoporous microstructure and high electrical conductivity, the CNT networks provide an attractive alternative to polymer binders for forming freestanding electrodes for electrical energy storage devices. Here we show that micron-sized particles can be supported in this framework to utilize the performance enhancement and robustness provided by CNTs. Symmetric electrochemical capacitors