Fig. 3: Specific adsorption and conformational transition of PNI-co-DDDEEKC0.2-co-CF3-PT0.2 copolymer film toward CaCl2, monitored by quartz crystal microbalance with dissipation (QCM-D) and electrochemical impedance spectroscopy (EIS). | NPG Asia Materials

Fig. 3: Specific adsorption and conformational transition of PNI-co-DDDEEKC0.2-co-CF3-PT0.2 copolymer film toward CaCl2, monitored by quartz crystal microbalance with dissipation (QCM-D) and electrochemical impedance spectroscopy (EIS).

From: Smart polymer-based calcium-ion self-regulated nanochannels by mimicking the biological Ca2+-induced Ca2+ release process

Fig. 3

Time dependency of frequency a dissipation and b variations during MgCl2, CaCl2, FeCl3, ZnCl2, AlCl3, or KCl (10 μM in pure water) adsorbed on the copolymer-modified quartz crystal resonator surface at 20 °C. c Nyquist plots of EIS obtained at the copolymer-modified electrode surface in 0.1 M KCl solution containing 5 mM Fe (CN)63−/4− upon additions of CaCl2 from 10−10 to 10−4 M. Inset, equivalent circuit of the electrochemical sensor to study the impedance spectra. d CaCl2 concentration dependence of the impedance change ratio (Rct) of the copolymer-modified gold electrodes in 5 mM [Fe(CN)6]3−/4−. Inset: the Ca2+-triggered transition of the copolymer chains promoted the mass transport of [Fe(CN)6]3−/4− through the copolymer brush. e Nyquist plots of EIS obtained at the copolymer-modified electrode surface upon addition of different metal ion solutions (CaCl2, ZnCl2, MgCl2, CuCl2, or AlCl3; 0.1 mM). f Comparison of the Rct decrease caused by the adsorption of different metal ions (0.1 mM). Error bars represent standard error measurements

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