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In this article, polyaniline nanofibers (PANI-NF)/manganese dioxide composites (PANI/MnO2) were synthesized through an interfacial polymerization approach. The PANI-NF and MnO2 were obtained by in situ oxidation of aniline by potassium permanganate and in situ reduction of potassium permanganate by aniline, respectively. During the interfacial polymerization, the monomer aniline can only be oxidized to PANI after it diffuses into the water phase. This diffusion-control feeding process of the monomer results in nanofiber structure. The morphologies and crystal structures of the prepared PANI/MnO2 composites were measured by scanning electron microscopy and x-ray diffraction. The supercapacitive behaviours of these composites were analysed by cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) tests. The CV and GCD tests indicate that the PANI/MnO2 composites possess better electrochemical activity and higher capacitive properties compared to neat PANI nanofibers. The specific capacitance of PANI/MnO2 composites and PANI-NF are 751 F g−1 and 180 F g−1 at 0.2 A g−1 in Na2SO4 solution, respectively. We believe that the enhanced capacitive properties are related to the special nanostructure and strong interaction between PANI and MnO2 that resulted from the interfacial synthesis method.

In this paper, we demonstrate a simple approach to improve the electrochromic performances of polyaniline (PANI) by incorporating PANI nanofibers (PANI-NFs) synthesized by interfacial polymerization into water-soluble PANI:poly(styrene sulfonate) (PANI:PSS). The one-dimensional PANI-NFs endow spin-coated PANI film high electrochemical activities and electrochromic properties. The structures and morphologies of PANI-NFs were characterized by FTIR spectroscopy and SEM observation. The electrochemical behaviors of PANI/PANI-NFs composites were analyzed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The electrochromic properties of composites were tested using electrochemical working station combining a UV-Vis spectrometer. The results show that the PANI-NFs with even diameter of ~ 30 nm can be synthesized easily using interfacial polymerization method. With the increasing of feeding amount of PANI-NFs, the oxidation peaks of CV curves shift to low potential direction, indicating enhanced electrochemical activities. The electrochromic test confirms that the PANI/PANI-NFs composites films have higher electrochromic contrast of 0.67 as comparison to 0.49 of PANI:PSS film. The PANI/PANI-NFs also exhibit excellent electrochromic stability. After 2000 cycles switching, only less than 4% contrast decay is observed. The enhanced electrochromic properties can be attributed to the small charge-transfer resistance and facile ion diffusion process brought by PANI-NFs. The EIS tests exhibit that with incorporating of highly conductive PANI-NFs, the PANI/PANI-NFs composites possess relatively lower charge-transfer resistance of 76 Ω as comparison to 94 Ω of neat PANI:PSS.

In this paper, the covalently bonded polyaniline (PANI) nanofiber/multi-walled carbon nanotubes (MWCNT) composites were synthesized via interfacial polymerization of aniline with para-phenylenediamine functionalized MWCNT at the interface of oil/water system. Owing to the diffusion-controlled growth process of PANI, PANI with uniform fiber structure were obtained. The morphology analysis showed that the diameter of PANI nanofiber decreased with the increasing of MWCNT loading amount. Impedance analysis showed that the charge-transfer resistances of the composites were reduced also with the increasing of MWCNT loading amount. The decreasing of charge-transfer resistances and change of morphology resulted in enhanced capacitive properties. Electrochemical tests showed that the specific capacitance of PANI, PANI/MWCNT-10% and PANI/MWCNT-20% were 405, 641 and 764 F·g-1, respectively. As comparison with pure PANI nanofiber, the specific capacitance of the composites increased by 58% and 88.6%, respectively.

Cortical sensory processing is modulated by behavioral and cognitive states. How this modulation is achieved by changing synaptic circuits remains largely unknown. In awake mouse auditory cortex, we found that sensory-evoked spike responses of layer 2/3 (L2/3) excitatory cells were scaled down with preserved sensory tuning when mice transitioned from quiescence to active behaviors, including locomotion, whereas L4 and thalamic responses were unchanged. Whole-cell voltage-clamp recordings revealed that tone-evoked synaptic excitation and inhibition exhibited a robust functional balance. The change to active states caused scaling down of excitation and inhibition at approximately equal levels in L2/3 cells, but resulted in no synaptic changes in L4 cells. This lamina-specific gain control could be attributed to an enhancement of L1-mediated inhibitory tone, with L2/3 parvalbumin inhibitory neurons also being suppressed. Thus, L2/3 circuits can adjust the salience of output in accordance with momentary behavioral demands while maintaining the sensitivity and quality of sensory processing.