Self-assembly of carbon nanotubes in polymer melts: simulation of structural and electrical behaviour by hybrid particle-field molecular dynamics

Self-assembly processes of carbon nanotubes (CNTs) dispersed in different polymer phases have been investigated using a hybrid particle-field molecular dynamics technique (MD-SCF). This efficient computational method allowed simulations of large-scale systems (up to ∼1 500 000 particles) of flexible rod-like particles in different matrices made of bead spring chains on the millisecond time scale. The equilibrium morphologies obtained for longer CNTs are in good agreement with those proposed by several experimental studies that hypothesized a two level "multiscale" organization of CNT assemblies. In addition, the electrical properties of the assembled structures have been calculated using a resistor network approach. The calculated behaviour of the conductivities for longer CNTs is consistent with the power laws obtained by numerous experiments. In particular, according to the interpretation established by the systematic studies of Bauhofer and Kovacs, systems close to "statistical percolation" show exponents t ∼ 2 for the power law dependence of the electrical conductivity on the CNT fraction, and systems in which the CNTs reach equilibrium aggregation show exponents t close to 1.7 ("kinetic percolation"). The confinement effects on the assembled structures and their corresponding conductivity behaviour in a non-homogeneous matrix, such as the phase separating block copolymer melt, have also been simulated using different starting configurations. The simulations reported herein contribute to a microscopic interpretation of the literature results, and the proposed modelling procedure may contribute meaningfully to the rational design of strategies aimed at optimizing nanomaterials for improved electrical properties.

Conductive properties and mechanisms of different polymers doped by carbon nanotube/polypyrrole 1D hybrid nanotubes

Polymers doped by MPPy hybrid nanotubes with enhanced conductivity and a reduced amount of carbon nanotubes.

Self-assembly of miscible homopolymer/quasi-block copolymer blends/MWNT composites: a strategy to obtain ultralow electrical percolation threshold and mechanism

We utilized self-assembly of miscible polymer blends/CNTs composites to obtain ultralow electrical percolation threshold, with different results of both miscibility and glass transition temperature variations from antecedent works.

Depression in glass transition temperature of multiwalled carbon nanotubes reinforced polycarbonate composites: effect of functionalization

Acid functionalized MWCNTs/PC composites showed significant improvement in storage modulus upto 57% in glassy and 400% in rubbery region over pure polycarbonate.

Facile synthesis of silver-decorated reduced graphene oxide as a hybrid filler material for electrically conductive polymer composites

Nano silver-decorated reduced graphene oxide (Ag–RGO) sheets were synthesized by simply dissolving graphite oxide and silver nitrate inN,N-dimethylformamide and keeping the suspension at 90 °C for 12 h.