Functional carbon nanotubes for high-quality charge transfer and moisture regulation through membranes: structural and functional insights

Abstract

Functional single walled carbon nanotubes (SWCNTs) are assembled onto porous supports by using layer-by-layer (LBL) approaches. Directed nano-assembly of nanotubes is identified as a crucial factor for controlling the combined functions of hybrid-composite membranes, including charge and moisture transport. In both the cases, donor-acceptor interactions are indicated to be responsible for the rearrangement of nanotubes inside the LBL multilayer and their related properties. Aggregation and stratification of the carbon nanotubes along with the availability of selective-site interactions are complementarily investigated by using SEM, Raman and infrared spectroscopy, while high electrical charge and water vapor transfer are achievable, provided that a large number of connections and competitive interactions are allowed. Ohmic behavior is observed for all types of carbon nanotubes, even if better-quality charge transfer pathways are obtained with carboxylated conductive filaments. Likewise, assisted moisture regulation is succeeded when using functional filaments with the capability to establish competitive H-donor-acceptor interactions with water.

Integrated carboxylic carbon nanotube pathways with membranes for voltage-activated humidity detection and microclimate regulation

“…To ensure the build up of a uniform and homogeneous multilayer, SEM images of the film deposited onto the porous substrate ( Fig. [30][31][32] Indeed, the increase in the G/D band intensity ratio reveals a higher aggregate level in solution, while a lower cluster formation is detected for particle power and solid film (Fig. Indeed, the picture revealed the formation of a uniform and very tiny film onto the porous microarray.…”

Polysulfone‐based composite membranes with functionalized carbon nanotubes show controlled porosity and enhanced electrical conductivity

“…42,43 Recently it has been shown that functionalized CNTs can be good candidates for efficient charge transfer when incorporated into membranes. 44 It is quite logical that the functionalized nanotubes incorporated into membranes would have conductivities that would be better than those of the matrix. The values of the conductivities are given in Table VIII.…”

Photoactive Gel for Assisted Cleaning during Olive Mill Wastewater Membrane Microfiltration

“…Precisely, titanium oxide (TiO 2 ) nanoparticles (NPs) have been dispersed in polyacrylic acid (PAA) and patterned with poly (diallyldimethyl ammonium chloride) (PDDA) in a hybrid complex that is deposited onto the shell side of polyethylene (PE) hollow-fiber membranes via layer-by-layer (LBL) approach [ 20 , 21 , 22 ]. Commercial PE membranes, which are considered tricky to manage wastewater due to the very high susceptibility to fouling, have been chosen with the intent to demonstrate the real efficiency of the photoactive gel under specific working conditions.…”