Carbon Nanotube and Cellulose Nanocrystal Hybrid Films

Abstract

The use of cellulose nanocrystals (CNC) in high performance coatings is attractive for micro-scale structures or device fabrication due to the anisotropic geometry, however CNC are insulating materials. Carbon nanotubes (CNT) are also rod-shaped nanomaterials that display high mechanical strength and electrical conductivity. The hydrophobic regions of surface-modified CNC can interact with hydrophobic CNT and aid in association between the two anisotropic nanomaterials. The long-range electrostatic repulsion of CNC plays a role in forming a stable CNT and CNC mixture dispersion in water, which is integral to forming a uniform hybrid film. At concentrations favorable for film formation, the multiwalled nanotubes + CNC mixture dispersion shows cellular network formation, indicating local phase separation, while the single-walled nanotube + CNC mixture dispersion shows schlieren texture, indicating liquid crystal mixture formation. Conductive CNT + CNC hybrid films (5–20 μm thick) were cast on glass microscope slides with and without shear by blade coating. The CNT + CNC hybrid films electrical conductivity increased with increasing CNT loadings and some anisotropy was observed with the sheared hybrid films, although to a lesser extent than what was anticipated. Percolation models were applied to model the hybrid film conductivity and correlate with the hybrid film microstructure.

Thermal Behavior of Green Cellulose-Filled Thermoplastic Elastomer Polymer Blends

“…Cellulose is of a low price, low density, and exhibits depressed CO 2 emission during the thermal degradation process. In addition, natural fibers are annually renewable and fully biodegradable [20][21][22][23] important for sustainable development.…”

Applications of Nanocellulose/Nanocarbon Composites: Focus on Biotechnology and Medicine

“…The nanocellulose component in the nanocellulose/CNT composites is used in the form of nanofibrils and nanocrystals, and carbon nanotubes usually in the form of SWCNTs or MWCNTs. Similarly as in composites containing graphene and other carbon allotropes, cellulose nanoparticles facilitate the homogeneous dispersion of CNTs in aqueous environments (Figure 3b), where the two types of nanoparticles are linked by noncovalent interactions, e.g., hydrophobic and electrostatic interactions [42,46]. The dispersion of CNTs can be further facilitated by TEMPO-mediated oxidation of cellulose nanoparticles, which endows them with abundant anionic carboxyl groups [141].…”

Biomolecule‐Directed Carbon Nanotube Self‐Assembly

“…Pristine, [ 124] unknown, [ 123] a) oxidized [ 117,150] van der Waals, [ 124] unknown, [ 123] a) H-bond [ 117,150] Shear blade, [ 124] dip coating, [ 123] van der Waals, [ 117] shear flow (3D printed) [ 150] 2D aligned stripes, [ 123,124] lyotropic liquid crystal phase, [ 117] fiber (wearable electronics) [ 150] Oxidized (HNO 3 ) H-bond Shear flow (3D printed) Fiber (wearable electronics) [ 150] Agarose Oxidized Multiple noncovalent Shear flow Hydrogel (tissue engineering) [ 146] Lipids Pristine van der Waals Electrostatic, [ 126] entropy driven, [ 127] van der Waals [ 159] Multilamellar and inverted centered rectangular columnar packing, [ 126] intercalated hexagonal binary superlattice and lamellar, [ 127] fiber (sensor) [ 159] a) Authors only state a commercially available aqueous SWCNT dispersion.…”

“…In a similar study, fiber alignment was achieved by controlled dip coating, [123] as well as ambient dry and shear blade deposition techniques, where additional aqueous stability was attributed to hydrophobic interactions between the CNC (200) surface and the aromatic SWCNT. [124]…”