| With the development of nanotechnology, the synthesis of conducting polymers with special micro/nano structures including nanotubes, nanofibers and nanopores and the property control and improvement become a hot issue in nanoscientific researches. In this work, soft- and ice-template synthesis methods have been utilized to fabricate nanowires and nanopores polyaniline (PANI), respectively. The preparation manipulation of morphologies, chemical structures and electrochemical properties was analyzed and studied. Based on these nano-PANI, high quality pH sensing electrodes were obtained. The different sensing properties by two different template methods were presented for a comparison. Such nano-PANI showed great potential in the sensor area.In the soft-templating synthesis, with camphorsulfonic acid (CSA) doping, PANI with nanofibers, nanodentrites and nanowires were obtained by adjusting reaction conditions, including concentration, temperature, time and molar ratio of CSA to aniline (AN). The influence on morphologies, chemical structures and electrochemical properties was investigated. Nanowires PANI with the best properties could be synthesized at the condition of 0.02 M AN concentration,0℃,72 h and CSA/AN=0.5In the ice-templating synthesis, nanoporous PANI was fabricated at -25℃, with CSA/AN=0.5. The morphology of nanopore was affected by molar ratio of CSA to AN.Compared with nanofibrous PANI, nanoporous PANI showed much better electrochemical properties due to more quinoid rings and smaller resistance.Several high sensitive pH electrodes were prepared and studied by modified with different structures nano-PANI. Nano-PANI exhibited good linear sensing to pH over 20 days. Comparing to nanofibrous PANI, nanoporous PANI synthesized with ice templates provided sharper sensing line (51.5 mV/pH), wider sensing area (from 2 to 8), faster sensing speed (28 s/pH) and better reversibility, resulting in great potential in the application of pH sensor. |
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