Controlling Non-Covalent Interactions to Modulate the Dispersion of Fullerenes in Polymer Nanocomposites

Abstract

Polymer nanocomposites (PNCs) are materials based on a class of filled plastics that contain relatively small amounts of nanoparticles, which can impart improved structural, mechanical, and thermal properties relative to the neat polymer. However, the homogeneous dispersion of the nanoparticles into a polymer matrix is critical and an impeding factor for the controlled enhancement of PNC properties. In this work, we provide new insight into the importance of polymer chain connectivity and nanoparticle shape and curvature on the formation of noncovalent electron donor–acceptor (EDA) interactions between polymers and nanoparticles. This is accomplished by experimentally monitoring the dispersion of nanoparticles in copolymers containing varying amounts of functional moieties that can form noncovalent interactions with carbon nanoparticles with corroboration through density functional calculations. The results show that the presence of a minority of interacting functional groups within a polymer chain leads to an optimum interaction between the polymer and fullerene. Density functional theory calculations that identify the binding energy and geometry of the interaction between the functional monomers and fullerenes correspond very well with the experimental results. Moreover, comparison of these results to similar studies with single-walled carbon nanotubes (SWNT) indicate a distinct difference in the ability of EDA interactions to improve the dispersion of fullerenes relative to their impact on SWNT. Thus, the polymer chain connectivity, the polymer chain conformation, and size and shape of the nanoparticle modulate the formation of intermolecular interactions and directly impact the dispersion of the resultant nanocomposite.

Controlling effective interactions and spatial dispersion of nanoparticles in multiblock copolymer melts

“…Of relevance to our present work is the recent experimental discovery that improved particle dispersion can be achieved by using chemically heterogeneous, amorphous copolymers. 22 Specifically, AB random copolymers (RCP) of intermediate composition, where the A and B monomers display different wettability with the particle, results in major improvement of the dispersion of fullerenes relative to both the corresponding pure homopolymers. By combining the Polymer Reference Interaction Site Model (PRISM) integral equation theory and computational chemistry input, a predictive understanding of this phenomenon for fullerenes in RCP melts has been achieved.…”

30 years of advances in functionalization of carbon nanomaterials for biomedical applications: a practical review

“…It was rationalized that the protonated porphyrin-fullerene complex is stabilized by p-p interactions. In another manifestation of electron donor-acceptor interactions, Teh, S-L. et al 39 have demonstrated the dispersion of C 60 in a polymer matrix, Fig. 2(c).…”

Self-Cleaning Photocatalytic Polyurethane Coatings Containing Modified C60 Fullerene Additives

“…The way in which additive incorporation affects T g can afford insight into intermolecular interactions between the additive and polymer. Increase in T g resulting from additive incorporation indicates increased intermolecular interactions that limit polymer mobility [36]. Unmodified Tecoflex exhibits a glass transition that spans a broad temperature range.…”