Surface diffusion of polymers on carbon nanotubes

Carbon nanotubes (CNTs) are emerging materials with a wealth of applications in different areas, ranging from molecular devices and sensors to drug delivery. However, pristine CNTs tend to bundle into strongly bound aggregates due to van der Waals interactions. This is a drawback, since many applications require individually dispersed CNTs. One possibility to overcome this problem is to use non-covalent dispersants such as surfactants or polymers, which can exfoliate and stabilize CNTs in aqueous solutions. However, non-covalent dispersion is still poorly understood at molecular level [1]. In what concerns polymers as dispersants, two main qualitative models on the polymer-CNT interaction are wrapping where polymers coat the CNT in a tight contact and loose adsorption where a weaker interaction between the polymer and the CNT takes place, so that the bound polymer remains almost like in its natural state in a good solvent, i.e. a random coil [2].