Tensor 2 ftir spectrometer

The interaction of functional groups in different films was evaluated by TENSOR II FT‐IR Spectrometer (Bruker). All infrared spectra were recorded at room temperature (25 ± 1°C) in absorbance from 4000 to 400 cm⁻¹ wavenumber.

Organic groups in the macroalgal protein
extracts were determined
using FT-IR spectroscopy (Bruker Tensor II FTIR spectrometer equipped
with the ATR diamond module (Bruker Optics, Germany)). All of the
spectra were an average of 18 scans from 4000 to 400 cm^–1 at a resolution of 4 cm^–1.

The transmission electron microscopic (TEM) image was acquired on a JEM-2100 transmission electron microscope (JEOL, Tokyo, Japan). The elemental analysis of C, H, and N content was performed on an Analysensysteme vario EL cube organic elemental analyser (Elementar, Hanau, Germany) while the elemental analysis of Cl content was carried out on a multi EA^® 4000 Elemental Analyzer (Analytik Jena AG, Jena, Germany). The Fourier transform infrared spectrum (FTIR) was performed on a Tensor II FTIR spectrometer (Bruker, Bremen, Germany). The UV-vis spectra were recorded on a UV-2550 absorption spectrophotometer (Shimadzu Co., Ltd., Tokyo, Japan) and the photoluminescence (PL) spectra were carried out on a RF-5301PC fluorescence spectrophotometer (Shimadzu Co., Ltd., Tokyo, Japan). Fluorescence lifetime assays were carried out on a FLS-980 fluorescence spectrophotometer (Edinburgh Instruments Ltd., Livingston, England).

To analyze the functional groups and provide information on the structural properties of the samples, FTIR spectroscopy was implemented by a Tensor II FTIR spectrometer (Bruker). Wavelengths of all spectra were recorded at 4000–400 cm⁻¹ (Elnaz & Saeed, 2020 (link)).

Transmission electron microscopy (TEM) images were collected using JEOL 200CX at 300 kV. X-ray diffractometry (XRD) measurement was performed on a Rigaku D/MAX-2250 V X-ray diffractometer at Cu Kα (λ = 0.154056 nm) within the 2θ range of 20–90° at a scanning rate of 5°/min. Fourier transform infrared (FT-IR) spectra were obtained using a Bruker Tensor II FTIR spectrometer. X-ray photoelectron spectroscopy (XPS) plots were detected by Shimadzu, AXIS SUPRA. Zeta-potential data were collected with Nicomp Z3000 SOP. Ultraviolet-Visible (UV-Vis) absorption spectra were recorded on Shimadzu UV-3600 Plus. An infrared thermal imager (FLIR A325SC camera) was used to record temperature changes and thermal image information. MTT assays were conducted with a Spark™ multimode microplate reader. Confocal laser scanning microscopy (CLSM) images were obtained using a Nikon A1+R-980 confocal microscope.

50-layer pairs of PDADMA/PAA PEMs
were prepared on a Germanium
(Ge) FTIR crystal using an automated Carl Zeiss HMS slide stainer.
First, PDADMA and PAA solutions were prepared at 0.15 M and pH 3 to
match the final total concentration of the prepared PECs at a 1:1
mixing ratio. The Ge substrate was cleaned with acetone before deposition.
The first layer was deposited by dipping the Ge substrate in PDADMA
solution for 15 min, followed by three separate rinse steps for 2,
1, and 1 min in Milli-Q water at pH 3. The second layer was deposited
by dipping in the PAA solution, followed by three similar rinses.
These two steps were repeated a total of 50 times to form 50 layer-pairs.
The PEMs were dried under ambient conditions overnight before VT-FTIR
spectroscopy measurements.
The coated Ge FTIR crystal was fitted
in a custom-made sample stage from Harrick Scientific Products Inc.
connected to a Bruker Tensor II FTIR spectrometer. First, background
spectra of the bare Ge crystal were collected at 10 °C intervals
from 27 to 75 °C. FTIR spectra were recorded from 4000 to 600
cm^–1 at a resolution of 2 cm^–1 in the attenuated total reflectance (ATR) mode at each studied temperature
in triplicates.