Yuanming Deng

CuO based inorganic-organic hybrid nanowires: a new type of highly sensitive humidity sensor

The organic surfactant template method has been widely used for the preparation of CuO nanorods, nanotubes and nanowires. However, the surfactants in this system have no effect on the properties of the final products because they are flushed away. In this work, we used this method to synthesize a novel type of inorganic-organic hybrid nanowire via the hybridization between CuO and amphiphilic oligomer octadecyl, polyethylene glycol di-butenetrioate (O-B-EG-B). Here O-B-EG-B, as a structure director, was not flushed away but remained in the prepared hybrid nanowires because it was bound around CuO or entrapped in interior CuO. The hybrid nanowires showed CuO cores and P(O-B-EG-B) shells when the concentration of O-B-EG-B was 0.4 mg ml(-1), but exhibited P(O-B-EG-B) cores and CuO shells when the concentration of O-B-EG-B was 4.0 mg ml(-1). We found that the hybrid nanowires with P(O-B-EG-B) cores and CuO shells could sense a slight change in the relative humidity (RH) and respond by rapidly changing their conductivity. The resistance changed by about two orders of magnitude within the humidity range from 5% to 83.8%. Moreover, a humidity sensor based on this type of nanowire not only showed long-term stability but also exhibited excellent reversibility to moisture changes in air.

Synthesis of walnut-like hierarchical structure with superhydrophobic and conductive properties

Walnut-like structures made up of a polyaniline (PANI) nanofiber network and polystyrene (PS) microspheres are successfully fabricated by a novel approach, “competitive adsorption–restricted polymerization”. In the reaction system, PS microspheres are simultaneously encapsulated by cationic surfactant and aniline hydrochloride. Just this cationic surfactant molecule affects the nucleation model and second growth of PANI via electrostatic interactions and steric hindrance, which accounts for the formation of a PANI nanofiber network coating on the PS surface. The size, ordering and amount of PANI nanofibers on the three-dimensional surface can be particularly controlled by altering a variety of synthetic conditions, such as the amount of cationic surfactant, temperature and concentration. A superhydrophobic and conductive surface is obtained by drop-casting a suspension of these walnut-like PS/PANI particles onto a substrate.

Waist cross-linked micelles synthesized viaself-assembly guiding radical polymerization

Amphiphilic micelles with waist cross-linked structure exhibit both core–shell reversing behavior and thermal sensitivity.

Heterogeneous silver-polyaniline nanocomposites with tunable morphology and controllable catalytic properties.

This paper introduces not only a simple hydrothermal route to silver-polyaniline (Ag-PANI) nanocomposites with controllable morphology, but also a type of catalyst possessing tunable and switchable catalytic capability. Ag-PANI Janus nanoparticles (NPs) and Ag@PANI core-shell NPs have been constructed successfully at different hydrothermal temperatures. The diameter of both Ag and PANI hemispheres of Janus NPs, as well as the PANI shell thickness of core-shell NPs, was finely tuned via adjustment of the feed ratio. We also gained a deeper insight into the functionalities of PANI components in the catalytic capability of the heterogeneous catalysts, choosing catalytic reductions of nitrobenzene (NB) and 4-nitrophenol (4-NP) as model reactions. Our results showed that the catalytic capability of the nanocomposites was dependent on the PANI morphology and hydrophobicity. The PANI shell coating on Ag NPs can concentrate the lipophilic NB, thus leading to an enhanced catalytic capability of Ag@PANI core-shell NPs. However, this enhanced catalytic capability was not observed for Ag-PANI Janus NPs when catalytically reducing NB. More importantly, the catalytic capability of the core-shell NPs in the reduction of hydrophilic 4-NP is switchable by varying the PANI shell from an undoped to a doped state.

Three-dimensional gold nanodendrimers: never conglomerating nanocatalyst

3D Au nanodendrimers constructed by radially arranged thin nano-sheets show tunable morphology and diameter. The unexpectedly large specific surface area resulting from the novel porous nanostructure makes the 3D Au nanodendrimers exhibit high catalytic activity and long service life.