Bws465 785s

The micromorphology of OIM@PAM was observed by scanning electron microscope (ZEISS EV0 MA15, Carl Zeiss, Dublin, CA, USA) with the accelerating voltage of 20 kV. The structure of OIM@PAM was measured by a fourier-transform infrared analyzer (Nicolet 6700, Thermo Scientific, Waltham, MA, USA) with a wavelength range of 500 cm⁻¹–4000 cm⁻¹. Thermo-gravimetric analysis (DSC823, METTLER TOLEDO, Greifensee, Switzerland) was employed to estimate the loaded amount of OIM at a heating rate of 10 °C/min in a temperature range of 40–600 °C in the N₂ atmosphere. The tensile test of OIM@PAM mainly referred to the ASTM standard D822 at room temperature in atmosphere, which was measured by an electronic universal testing machine (ETM502C, Wance Co. Ltd., Shenzhen, China) with the crosshead speed of 5 mm/min [58 (link)]. Each sample was measured three times to guarantee the accuracy of the results. A raman spectrometer (BWS465–785S, B&W TEK, Newark, DE, USA) was used to study the OIM adsorption behavior at the L80 steel/corrosive solution interface. The selected laser wavelength was 785 nm.

SERS spectra were acquired using a portable Raman spectrometer, the BWS465-785s from BWTEK in Shanghai, China. The SERS enhancement of the synthetic Au@Ag NRs substrate was evaluated using 4-mercaptobenzoic acid (4-MBA) standard. Briefly, 10 μL10⁻³ M 4-MBA was mixed with 1000 μL synthetic AuNRs and Au@Ag NRs. After incubation for 10 min, 10 μL mixture was dropped on the glass slide for SERS detection. Then, different concentrations of 4-MBA (10⁻⁷ M, 10⁻⁸ M, 10⁻⁹ M, 10⁻¹⁰ M, 10⁻¹¹ M) were detected to analyze the SERS detection sensitivity. The parameter settings of the instrument were excitation wavelength (785 nm), power (50%), integration time (10,000 ms) and accumulation (3 times).
Detection of MG based on Au@Ag NRs substrate were performed as following. Firstly, 100 μL of different concentrations of MG solution (5 × 10⁻⁹ M~2 × 10⁻⁷ M) was mixed with 100 μL Au@Ag NRs substrate and 30 μL of 0.1 M NaCl, respectively. Subsequently, 10 μL of the mixed solution was dropped on the glass slide for detection after incubation for 10 min. The parameters of SERS detection are the same as the 4-MBA standard test, except for the power (100%).

The starch sample was placed in the cap of a centrifuge tube and pressed flat to make its surface smooth. The sample was measured using a portable Raman spectroscopy system (BWS465-785S, B&W Tek, Plainsboro Township, NJ, USA), and the full width at half maxima (FWHM) of the characteristic peak near 480 cm⁻¹ was calculated using software to determine the short-range ordered structure of starch.