Layer-by-Layer Assembled Composites from Multiwall Carbon Nanotubes with Different Morphologies

Abstract

We report formation of polyelectrolyte/multiwall carbon nanotube (MWNT) multilayers by the layer-by-layer assembly technique. Both "hollow" and "bamboo" type MWNTs were employed. Scanning electron and atomic force microscopy indicate high structural homogeneity of the prepared composites. Ellipsometry and the absorbance spectroscopy confirm sequential adsorption of oppositely charged nanotubes and the polyelectrolyte resulting in uniform growth of the polyelectrolyte/MWNT films. Measurements of the mechanical properties show that these are strong composite hybrid films with mechanical properties exceeding many carbon nanotube composites made by mixing, or in-situ polymerization. Bamboo-type carbon nanotube composites display ultimate tensile strength of 150 ± 35 MPa and Young modulus of 4.5 ± −0.8 GPa as compared to 110 ± 25 MPa and 2 ± 0.5 GPa in composites made from common hollow MWNTs. This indicates that the morphology of the fibers can substantially improve matrix connectivity on the material mitigating "telescopic effect" in MWNTs. The films made from bambootype MWNTs approach in strength recently reported layer-by layer composite films from single wall carbon nanotubes, while being substantially less expensive. These results confirm the potential of the layering method for the manufacturing of composites with high load of strong filler and importance of uniform distribution and good interconnectivity between carbon nanotubes and the polymer matrix.

Carbon Nanotube and Gold‐Based Materials: A Symbiosis

“…The same properties of the SDS-functionalized MWNTs were also demonstrated to be useful for mediating the attachment of AuNPs onto the surface of the tubes. This strategy [66][67][68] through a noncovalent approach may be superior to those of using covalent approaches due to the ability to maintain the electrical and structural properties of the CNTs. Further applications of the LBL-assembled CNT multi-layer films and the AuNPs/ MWNT nanohybrids are in the development of bio-electronic nanodevices such as biosensors and biofuel cells.…”

Tailoring Piezoresistive Sensitivity of Multilayer Carbon Nanotube Composite Strain Sensors

“…As opposed to creating a stratified multilayer thin film, newly adsorbed polyelectrolytes are capable of interpenetrating previously deposited layers to form multilayer homogeneous composites (Lo¨sche et al, 1998). Adsorption of each monolayer is based on opposite charge electrostatic and van der Waals force attraction to the preceding monolayer (Mamedov et al, 2002;Rouse and Lillehei, 2003;Olek et al, 2004).…”

Penicillin biosensor based on a capacitive field-effect structure functionalized with a dendrimer/carbon nanotube multilayer

“…Carbon nanotubes (CNTs) are attractive for (bio-)chemical sensors because of their unique properties, which in most cases arise from the combination of electrical and chemical properties and nanosized dimensions (Balasubramanian and Burghard, 2006;Kim et al, 2007;Allen et al, 2007;Byon and Choi, 2006). One simple, versatile method to assemble dispersed CNTs is the layer-by-layer (LbL) technique, which offers fine control over film thickness and architecture (Hammond, 2004;Tang et al, 2006;Ariga et al, 2007), making it possible to combine different materials in a synergistic way (Jiang et al, 2004;Olek et al, 2004;Zucolotto et al, 2006;Siqueira et al, 2006Siqueira et al, , 2007Xue et al, 2006;Zucolotto et al, 2007). As a building unit for the multilayer films in biosensors, CNTs have often been combined with polyelectrolytes and highly branched dendritic macromolecules (Yang et al, 2006;Siqueira et al, 2008;Siqueira et al, 2009).…”