Block Copolymer Nanocomposites Based on Multiwall Carbon Nanotubes: Effect of the Functionalization of Multiwall Carbon Nanotubes on the Morphology of the Block Copolymer

Abstract

Baytubes were kindly supplied by Bayer MaterialScience. Styroclear GH62 (AS-SB 26 ) was cordially provided by BASF. J.A. acknowledges a DAAD-HGF fellowship. The authors acknowledge financial support by the 7th Framework Programme of the European Commission (HARCANA (NMP3-LA-2008-213277)) and HASYLAB.Films based on a commercial block copolymer and multiwall carbon nanotubes (MWCNTs) were prepared by solution casting. The block copolymer has a star asymmetric chain architecture, with polystyrene chains of different lengths and a polybutadiene core. The block copolymer has a lamellar morphology. The MWCNT were grafted with polystyrene chains under atom transfer radical polymerization (ATRP) conditions. The nanocomposites were characterized by transmission electron microscopy (TEM) and simultaneous small angle X-ray scattering (SAXS)/strain-stress tests. The morphology of the nanocomposites is influenced by the polystyrene chain grafted from the MWCNT. In the case of the nanocomposite based on pristine MWCNT, most of the nanotubes intersect the lamellar domains of the block copolymer. With the increase of the molecular weight and the grafting chain density of the polystyrene anchored to the MWCNT, a favorable interaction between the polystyrene microdomain phases in the block copolymer and the MWCNT is observed. In the case where the MWCNT grafted with the relative highest molecular weight (20 kgÁmol À1 ) and polystyrene grafted content (> 90 wt%), the MWCNT locally templates the lamellar morphology of the block copolymer. The effect on the block copolymer is analyzed based on the orientation of the morphology under an external deformation.

Influence of surface modification of carbon nanotubes on interactions with polystyrene‐b‐polyisoprene‐b‐polystyrene matrix and its photo‐actuation properties

“…In the case of MWCNT‐PS, the physical cross‐linking is stabilized, resulting in much more stable baseline. However, the presence of the polystyrene chains on the MWCNT surface is a precondition of the preferential localization of MWCNT‐PS in the hard polystyrene phase, thus decreasing the possibility of efficient transfer of the energy to polyisoprene chains responsible for actuation. Therefore, the photo‐actuation changes in this case are lower in comparison with neat MWCNT.…”

Tailoring of viscoelastic properties and light-induced actuation performance of triblock copolymer composites through surface modification of carbon nanotubes

“…It is known that the fillers can be targeted to interact selectively with one phase of a block copolymer matrix. The location of filler inside blocks or at interface can be tailored by the chemical structure, molar mass and grafting density of the polymer chains [16]. Furthermore, nanoparticles specific interactions were shown to influence the materials properties, such as T g or viscoelastic performance [14,17,18].…”

Ordering of anisotropic nanoparticles in diblock copolymer lamellae: Simulations with dissipative particle dynamics and a molecular theory

“…nanostructures with high (>10) aspect ratio [16][17][18][19][20][21] (nanowires, nanotubes), the anisotropy of nanoparticles has so far received limited attention in spite of their shape abundance offered by synthetic chemistry. 22,23 Perhaps the simplest small anisotropic objects are nanorods, and their behavior in block copolymer films has been considered in Refs.…”