Single-Walled Carbon Nanotubes Spontaneous Loading into Exponentially Grown LBL Films

Exponentially growing layer-by-layer (e-LBL) assembled films attracts a lot of attention mostly due to multiple practical applications in biology and medicine. However, e-LBL was observed only for a very limited number of polymers. This fact inevitably limits the area of research and functionalitics that one can obtain for them. Also, it is fundamentally important to gain better understanding of the effect and importance of molecular flexibility for e-LBL films. Here we report that dispersions of rod-like nanocolloids such as single walled carbon nanotubes (SWNTs) and nanowires (NWs) can spontaneously bore into and stay in the e-LBL matrix. Molecular rigidity and surface charge appear to be the key parameters determining the possibility Of Such a process and its extent. SWNT forms a thick 2-25 mu m penetration layer, while insufficient flexibility leads to hedgehog structures in the case of CdTe and Te NA's. Electrical properties of the films obtained display fundamental differences with SWNT composites made by standard methods. They were attributed to thermal activation of vibrational modes of film components disturbing nanotube-to-nanotube tunneling. The dynamic nature of the e-LBL film combined with unique SWNTs properties can lead to a new type of smart materials and can help a better understanding of methods of morphological control in nanocomposites.