Xincai Liu

Synergic effect within n-type inorganic–p-type organic nano-hybrids in gas sensors

This paper describes the exploration of a synergic effect within n-type inorganic–p-type organic nanohybrids in gas sensors. One-dimensional (1D) n-type SnO2–p-type PPy composite nanofibers were prepared by combining the electrospinning and polymerization techniques, and taken as models to explore the synergic effect during the sensing measurement. Outstanding sensing performances, such as large responses and low detection limits (20 ppb for ammonia) were obtained. A plausible mechanism for the synergic effect was established by introducing p–n junction theory to the systems. Moreover, interfacial metal (Ag) nanoparticles were introduced into the n-type SnO2–p-type PPy nano-hybrids to further supplement and verify our theory. The generality of this mechanism was further verified using TiO2–PPy and TiO2–Au–PPy nano-hybrids. We believe that our results can construct a powerful platform to better understand the relationship between the microstructures and their gas sensing performances.

Preparation of unique PEDOT nanorods with a couple of cuspate tips by reverse interfacial polymerization and their electrocatalytic application to detect nitrite

By using Ce(SO4)2·4H2O as an oxidant and sodium bis(2-ethylhexyl) sulfosuccinate (AOT) as a surfactant, unique poly(3,4-ethylenedioxythiophene) (PEDOT) nanorods with a couple of cuspate tips were successfully prepared by reverse interfacial polymerization. The morphology of these PEDOT nanorods was very regular and well-dispersed with widths and lengths from one tip to another tip mostly in the range 40–60 nm and 370–460 nm, respectively. The chemical structure and formation mechanism of PEDOT nanorods are discussed in detail by several analysis methods. AOT played an important role during the formation of PEDOT nanorods. It could be combined with Ce4+ to form a unique template for the polymerization of 3,4-ethylenedioxythiophene (EDOT) in the cylindrical micelles formed by n-hexane, H2O and AOT. Furthermore, the application of PEDOT nanorod-modified glassy carbon electrode (GCE) as an electrochemical sensor for detecting nitrite was also investigated. Due to their good dispersibility and large surface area, PEDOT nanorods exhibited good linearity and sensitivity of cyclic voltammetry (CV) responses as well as amperometric responses for electrocatalytic oxidation of nitrite. It resulted in PEDOT nanorods acting as a good steady and sensitive electrode material for detecting nitrite.

One‐Dimensional Polyelectrolyte/Polymeric Semiconductor Core/Shell Structure: Sulfonated Poly(arylene ether ketone)/Polyaniline Nanofibers for Organic Field‐Effect Transistors

A polyelectrolyte/polymeric semiconductor core/shell structure is developed for organic field-effect transistors (OFETs) based on sulfonated poly(arylene ether ketone)/polyaniline core/shell nanofibers via electrospinning and solution-phase selective polymerization. The polyelectrolyte does not work as a gate dielectric, but can provide an internal modulation from the nanointerface of the 1D core/shell nanostructure. The transistor devices display very high mobilities.

Electroactive polymer with oligoanilines in the main chain and azo chromophores in the side chain: synthesis, characterization and dielectric properties

By an oxidative coupling polymerization approach, we have synthesized a novel electroactive polymer with good solubility containing alternating phenyl-capped aniline tetramer in the main chain and azo chromophores in the side chain. Dielectric properties of the as-synthesized polymer were investigated in detail and gratifying results have been observed. Firstly, a large enhancement in the dielectric constant was achieved utilizing the method of doping the conjugated oligoaniline segments with hydrochloric acid. Secondly, the adjustment of dielectric constant was implemented primarily by means of exposing the samples to UV and visible irradiation, mainly owing to the photoisomerization derived from azo chromophores in the side chain. The detailed characteristics of the as-synthesized polymer were systematically studied by Fourier-transform infrared (FTIR) spectra, nuclear magnetic resonance (1H NMR) and gel permeation chromatography (GPC). UV-vis spectra were used to monitor the photoisomerization and doping process of the polymer. The thermal characteristics of the polyamide were evaluated by thermogravimetric analysis (TGA). Moreover, the electrochemical activity of the polymer was explored by cyclic voltammogram (CV) measurement, showing that the intrinsic electroactivity of the oligoaniline was maintained in the polymer.

Fabrication of luminescent hybrid fibres based on the encapsulation of polyoxometalate into polymer matrices

Polyvinyl alcohol (PVA)/polyoxotungstoeuropate composite fibres were successfully prepared by a facile method called the electrospinning technique. Scanning electron microscopy (SEM) analysis revealed the fibre morphology of the composite. Transmission electron microscopy (TEM) showed spherical nanoparticles of the polyoxotungstoeuropate component with an average particle size of several nanometres to tens of nanometres and good dispersion. The electrospinning process prevented the polyoxometalate (POM) turning to an inhomogeneous microphase and large aggregation, so it is an effective and facile method for avoiding the phase separation of POM in the polymer matrices. X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and ultraviolet–visible (UV–vis) spectra were used to characterize the structure of PVA/polyoxotungstoeuropate composite fibres. The fluorescence properties of the composite fibres were also investigated.

Synthesis and properties of novel electroactive poly(aryl ether ketone) bearing oligoaniline segments

A novel hyperbranched electroactive azo copolymer with different oligoaniline segments was synthesized by an oxidative coupling polymerization approach, exhibiting an exciting molecular structure. The detailed characteristics of the obtained copolymer were systematically studied by Fourier-transform infrared (FTIR) spectra, nuclear magnetic resonance (1H NMR), gel permeation chromatography (GPC) and X-ray powder diffraction (XRD). The thermal resistance of the copolymer was investigated by thermogravimetric analysis (TGA). Through cyclic voltammogram (CV), we explored the electrochemical behavior of the copolymer. Moreover, photoisomerization process and doping process of the copolymer were monitored with UV–vis spectra. Dielectric properties of the as-synthesized copolymer were investigated in detail, and gratifying results have been reported. Firstly, a large enhancement in the dielectric constant was achieved utilizing HCl-doping of the conjugated oligoaniline segments. Secondly, the copolymer in HCl-doped form possessed much higher dielectric constants compared with the similar linear polymer, mainly due to the branched molecular architecture.

Novel electroactive aromatic polyamide with oligoanilines and azo groups in the backbone: synthesis, characterization and dielectric properties

A novel electroactive polyamide with alternating amino-capped aniline pentamer and azo groups in the main chain was synthesized via a four-step synthetic procedure. The characteristics of the obtained polyamide were studied in detail by Fourier-transform infrared (FTIR) spectra, nuclear magnetic resonance (1H NMR) and gel permeation chromatography (GPC). The thermogravimetric analysis (TGA) was used to evaluate its thermal characteristics, and the result showed the as-synthesized polymer had a good thermal stability. Besides, the electrochemical behavior of the polyamide was checked by cyclic voltammetry (CV) and the mechanism of electrochemical oxidation process was well studied. Furthermore, UV–vis spectra were used to monitor the doping process and photoisomerization process of the polyamide. Ratifying results were obtained in the investigation on dielectric properties of the as-synthesized polymer. The dielectric constant was greatly increased by treating the conjugated oligoaniline segments with hydrochloric acid.

The high performance of polydopamine-coated electrospun poly(ether sulfone) nanofibrous separator for lithium-ion batteries

In this work, electrospun poly(ether sulfone) (PES) nanofibrous membranes coated with hydrophilic polydopamine (PES-PDA) were successfully prepared. As a separator of lithium-ion batteries, the prepared PESPDA nanofibrous membrane shows ultrahigh porosity, due to the extra-large surface area of the nanofibers. Moreover, good thermostability of PES and polydopamine also results in the low shrinkage of the membrane under high temperature. As a result of the large number of amine groups and phenolic hydroxyl groups from the polydopamine, superior electrolyte wettability and high liquid electrolyte uptake capacity of the PES-PDA nanofibrous membrane have also been disclosed through comprehensive study, which would decrease the electrolyte absorption time and improve the performance of the battery. In the cell evaluation, an expected enhancement of cell performance with reduced polarization phenomenon and improved cycling stability is observed after coating with polydopamine, which certifies the validity of the polydopamine coating.

Synthesis and properties of a novel multifunctional hyperbranched polyamide

A novel hyperbranched polyamide containing azobenzene and oligoaniline groups (HPA-AO) has been synthesized by A2+BB’2 strategy. The structures of the obtained HPA-AO were confirmed via nuclear magnetic resonance (NMR) and Fourier-transform infrared spectra (FTIR); morphological data was ascertained via X-ray diffraction (XRD). The HPA-AO exhibited good thermodynamic stability. Due to the introduction of oligoaniline segments, the HPA-AO material was endowed with reversible electroactivity, and adjustable dielectric properties. Furthermore, the optical properties of HPA-AO were studied in detail and the results indicated that this azobenzene-containing polymer possessed expected photoisomerization, photoinduced birefringence and patterning properties.

Synthesis and electronic properties of comb-like polyamides bearing different contents of tetraaniline pendant groups

Comb-like polyamides bearing different contents of tetraaniline pendant groups were synthesized via nucleophilic polymerization coupled with a post-functionalization method, and exhibit excellent solubility, good thermal stability and interesting spectroscopic properties. Their electronic properties, including conductivity, dielectricity, electroactivity, electrochromism and anticorrosion, were effectively adjusted and controlled by importing different numbers of tetraaniline pendant groups.