Probing of polymer to carbon nanotube surface interactions within highly aligned electrospun nanofibers for advanced composites

Abstract

By electrospinning poly(ethylene oxide) (PEO)-blended sodium dodecyl sulfate (SDS) functionalized carbon nanotube (CNT) solutions, we engineered single-and double-walled nanotubes into highly aligned arrays. CNT alignment was measured using electron microscopy and polarised Raman spectroscopy. Mechanical tensile testing demonstrates that a CNT loading of 3.9 wt% increases the ultimate tensile strength and ductility of our composites by over a factor of 3, and the Young's modulus by over a factor of 4, to ∼260 MPa. Transmission electron microscopy (TEM) reveals how the aligned nanotubes provide a solid structure, preventing polymer chains from slipping, as well as polymer crystallisation structures such as 'shish-kebabs' forming, which are responsible for the improved mechanical properties of the composite. Differential scanning calorimetry (DSC) and small angle X-ray scattering (SAXS) reveals micellar and hexagonal columnar structures along the axis of the fibers, some of which are associated with the presence of the CNT, where these hexagonal structures are associated with the SDS functionalization on the CNT surfaces. This work demonstrates the benefits of CNT alignment within composites, revealing the effectiveness of the electrospinning technique, which enables significantly improved functionality, increasing the utility of the composites for use in many different technological areas.

Mechanisms of mechanical reinforcement by graphene and carbon nanotubes in polymer nanocomposites

“…152,153 A number of studies, such as the one of Cheng and coworkers 154 on polyacrylonitrile/MWCNT composite nanofibre sheets produced by electrospinning have reported an improvement in the mechanical properties. [155][156][157] More recently King et al 158 managed to engineer single-and double-walled CNTs into highly aligned arrays by electrospinning poly(ethylene oxide) and functionalized CNTs solutions (Fig. 9).…”

Low-Cost Catalyst Ink for Simple Patterning and Growth of High-Quality Single- and Double-Walled Carbon Nanotubes

“…The second alternative approach is to mass produce the CNTs first, through methods such as the fluidized bed method or continuous direct spinning and then apply post processing techniques to purify and manipulate CNTs into a device . Although the CNT fabrication in this approach is much more straight forward compared to the previously discussed method, there are a number of post processing steps needed, including: dispersion, purification, and manipulation or alignment. ,, This requires more processing steps, consumable materials (such as surfactants), and energy use. Furthermore, the precision allowed via lithography and CVD for the placement of CNTs in precise areas is not currently achievable.…”

“…10 Although the CNT fabrication in this approach is much more straight forward compared to the previously discussed method, there are a number of post processing steps needed, including: dispersion, purification, and manipulation or alignment. 6,11,12 This requires more processing steps, consumable materials (such as surfactants), and energy use. Furthermore, the precision allowed via lithography and CVD for the placement of CNTs in precise areas is not currently achievable.…”