Biomimetic channels based on carbon nanotubes (CNTs) with fast and selective transport have attractive applications in many fields. In this work, a remarkable and modulated enhancement in the ion transport rate through CNTs is facilitated by means of lipid decoration, by a factor of up to 20 times. A type of CNT membrane is firstly prepared, composed of well aligned multi-wall carbon nanotubes with an inner size of ∼10 nm. An inter-diffusion method is used to efficiently incorporate lipids within the CNTs. It is found that the lipid phase state as well as the surface property of the tubes' inner walls corporately determine the assembly behavior, such as location and stability of lipids, which further influence the ion transport rate through the tubes. For example, the incorporation and self-assembly of liquid-phase DOPC and polymerized Diyne-PC within the tubes induces an enhancement in steady ion transport rate through CNTs by a factor of 5 and 20 times, respectively. In contrast, the gel-phase DPPC prefers to stay at tube tips, which increases the ion transport rate during the initial stage only. This work provides a practical guide to regulate the ion transport behaviors through CNTs for versatile applications.

We demonstrate a general approach for attaining the bottom morphology of block copolymer (BCP) thin films. In our former measurements on PS-b-PMMA films, surface morphology maps of the BCP films revealed distinct ordering regimes where the cylinders orient predominantly perpendicular or parallel to the interface and an ‘intermediate’ regime where these morphologies coexist. However, this earlier work did not explore the bottom morphology of BCP thin films. In this study, we investigated the block copolymer morphology near the solid substrate in the cast block copolymer film having a perpendicular cylinder morphology on the surface.

Our study on poly(methyl methacrylate) (PMMA) films with fixed nanoparticles (NPs) on the supporting substrate, where the nanoparticles span the film thickness, reveal a three-stage evolution of wavelike undulations on the film surface: early stage, intermediate stage and late stage. The wavelike height undulations are induced by the compressive stresses, which are enhanced by introducing fix constrians (NPs) that resist the in-plane thermal expansion of the polymer film. We quantified the evolution of surface undulations, in an effort to understand the effect of solvent annealing on the undulations. The polymer chains in PMMA films prepared by spin coating are not fully equilibrated due to the rapid solvent evaporation during drying. Solvent annealing increases the molecular mobility and enables relaxation of the polymer network. This solvent treatment could perhaps give rise to an increase in entanglement density and associated film modulus. The surface undulations increase with the solvent annealing time before they reach the equilibrium values. The wavelike surface undulations might be associated with the entanglement density of polymer chains.The overall evolutionary process of wavelike surface undulations of nanoparticle-filled polymer thin films annealed in solvent vapor.

We demonstrate a novel nano-porous membrane of 10 nm diameter multiwall carbon nanotubes (MWCNTs) filled with thermally sensitive poly(N-isopropylacrylamide) (PNIPAm) hydrogel. High-resolution transmission electron microscopy (HRTEM), micro FT-IR spectroscopy and confocal laser scanning fluorescence microscopy are used to confirm that the MWCNTs are filled with the hydrogel. An improvement in the hydrophilicity of the gel-filled nano-channels is expected to promote the migration of aqueous solutions and the transportation of water. Meanwhile a decrease in ion flux is observed after the nano-pores of MWCNTs are filled with the hydrogel. This new hydrogel filled-CNT material shows potential for nano-chromatography, water purification and use as intelligent ionic channels.

We have investigated the interdiffusion of two dissimilar polymer species with different molecular masses, Mw, thus having different self-diffusion coefficients D*. A net mass flux across the interface and displacement of the original interface, Δx, between the two polymer films are observed. The displacement of the original interface moves toward the side containing the faster moving polymer species. We also examine the effect of an in-plane stationary temperature gradient on the interdiffusion of two dissimilar polymer species. As the low Mw polymer species is in the region of high temperature under the thermal gradient temperature field, the interface between the two polymer films moves faster compared with the system with the low Mw polymer species in the cold region of the temperature gradient field. We suggest that the in-plane thermal gradient accelerates polymer migration through the enhancement in polymer diffusion along the direction of the temperature gradient due to the Soret effect. We also find that the interdiffusion of polymers depends on the composition in the blend system. For a statistical copolymer system of plastic poly(ethylene-co-hexene) (PEH) and elastic poly(ethylene-co-butene) (PEB), having technologically interesting plastic and elastic properties, the diffusion of the relatively slow diffusion species (PEH) increases with the increase of PEB composition. Under the thermal gradient field the net mass flux across the interface and the movement of original interface between two polymer films can be controlled by the direction of the temperature gradient and composition of the blend system.

In this paper we report on an inter-diffusion polymerization method to encapsulate polyaniline (PANi) chains inside multiwalled carbon nanotubes (MWCNTs) based on CNT nano-porous membranes. The MWCNT's inner cavity with a diameter around 15 nm is designed to be the only path for the diffusion of the aniline monomer and the initiator, which achieves an efficient and controllable infilling of PANi inside the CNT cavity. The energy filtered transmission electron microscopy (EFTEM) and Raman spectroscopy confirm the successful encapsulation of PANi chains inside CNTs. The new PANi@CNT hybrid exhibits excellent gas sensitivity towards NH3 or HCl in a wide concentration range. This new method (inter-diffusion polymerization) is believed to be much more efficient and tunable in preparing novel endohedral nanotube materials compared to traditional capillary infilling approaches.

We demonstrate a novel nano-porous membrane of 10 nm diameter multiwall carbon nanotubes (MWCNTs) filled with thermally sensitive poly(N-isopropylacrylamide) (PNIPAm) hydrogel. High-resolution transmission electron microscopy (HRTEM), micro FT-IR spectroscopy and confocal laser scanning fluorescence microscopy are used to confirm that the MWCNTs are filled with the hydrogel. An improvement in the hydrophilicity of the gel-filled nano-channels is expected to promote the migration of aqueous solutions and the transportation of water. Meanwhile a decrease in ion flux is observed after the nano-pores of MWCNTs are filled with the hydrogel. This new hydrogel filled-CNT material shows potential for nano-chromatography, water purification and use as intelligent ionic channels.

In this paper we report on an inter-diffusion polymerization method to encapsulate polyaniline (PANi) chains inside multiwalled carbon nanotubes (MWCNTs) based on CNT nano-porous membranes. The MWCNT's inner cavity with a diameter around 15 nm is designed to be the only path for the diffusion of the aniline monomer and the initiator, which achieves an efficient and controllable infilling of PANi inside the CNT cavity. The energy filtered transmission electron microscopy (EFTEM) and Raman spectroscopy confirm the successful encapsulation of PANi chains inside CNTs. The new PANi@CNT hybrid exhibits excellent gas sensitivity towards NH3 or HCl in a wide concentration range. This new method (inter-diffusion polymerization) is believed to be much more efficient and tunable in preparing novel endohedral nanotube materials compared to traditional capillary infilling approaches.