Frontier ft ir spectrometer

Transmission FTIR spectra were recorded with a PerkinElmer FT‐IR Spectrometer “Frontier” on p[p(g₄2T‐T)‐co‐U] drop‐cast from DMSO (10 g L⁻¹) onto CaF₂. Variable‐temperature transmission FTIR was done by heating from 22 to 220 °C using a Specac electrical heating jacket equipped with a Specac 4000 series temperature controller (West 6100⁺).

The absorption spectra were acquired on Edinburgh Instruments FS5 (Edinburgh Instruments Ltd., Livingston, UK). The FTIR and XPS analysis were obtained with an FTIR SPECTROMETER FRONTIER (Perkin Elmer Inc., Waltham, MA, USA) and PHI Hybrid Quantera (ULVAC-PHI). The concentration of Au nanomaterials was measured with an OPTIMA 2000DV (Perkin Elmer Inc., Waltham, MA, USA), and TEM images were obtained using a JEM-1400 (JEOL Ltd., Akishima, Tokyo, Japan). Hydrogen tetrachloroaurate (III) trihydrate (HAuCl₄·3H₂O, ≥99.9%) and cetyltrimethylammonium bromide (CTAB, ≥99%) were purchased from Alfa Aesar (Heysham, Lancashire, UK). Sodium citrate dihydrate (≥99%) was acquired from Avantor Inc. (Radnor, PA, USA). Sodium borohydride (NaBH₄, ≥99%) was obtained from Koch-Light Laboratories Ltd. (Haverhill, England, UK). Sulfuric acid (≥98%) and L-ascorbic acid (≥99%) were purchased from Fluka (Charlotte, NC, USA). Silver nitrate (AgNO₃, 99.85%) was obtained from Acros Organics (Waltham, MA, USA). L-cysteine (≥97%) was purchased from Merck KGaA Ltd. (Darmstadt, Germany). Ultrapure deionized water (18.3 MΩ·cm⁻¹, RODA, Te Chen Instruments CO., Ltd., Taichung, Taiwan) was used for all solution preparations. All chemicals were used as received, without further purification.

Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy (Perkin Elmer, Waltham, MA, USA) was carried out to qualitatively identify the constituents of untreated and untreated abaca fibers. Test results were obtained using Perkin Elmer FTIR Spectrometer Frontier with ATR accessory in the range of 4000–650 cm⁻¹. The ATR cell is equipped with a trapezoidal diamond crystal as the internal reflection element. Baseline correction was applied to the spectrum to improve its quality without distorting the band intensities in the final spectrum.

The surface morphology of the test samples was examined using a field emission-scanning electron microscope (FE-SEM; JSM7600, JEOL Ltd., Tokyo, Japan). Surface roughness values (arithmetic average roughness (Sa) and root-mean-square height (Sq)) were obtained using a 3D profilometer (Profilm 3D, KLA-Filmetrics, San Diego, USA) with a scanning area of 230 µm × 150 µm and Gaussian filter size (cutoff) of 25 μm. The sessile solid drop method was used to evaluate the wettability (or hydrophilicity) and surface energy. Deionized water and diiodomethane were used as representative polar and non-polar liquids. A contact angle goniometer (100SB, Sindatek, New Taipei City, Taiwan) was used to capture the side view of the liquid droplet on the sample surface, and then the contact angle was measured. The corresponding software Magic Droplet was used to calculate the surface energy using the Owens–Wendt method [30 (link)]. The abovementioned measurements were averaged from measurements performed in triplicate. The sample size for each measurement was 5. Functional groups on the surface of test samples were also analyzed using attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR; FT-IR Spectrometer Frontier, PerkinElmer Inc., Waltham, MA, USA).

Transmission FTIR and ATR-FTIR measurements were conducted using an FTIR Spectrometer Frontier (PerkinElmer, Inc., USA). The Si substrates used for ATR-FTIR analysis were obtained from R-DEC Co. To enable a fair comparison with the transmission FTIR spectra, the ATR-FTIR spectra were corrected by dividing them by the wavelength λ. This correction accounts for the fact that the absorbance in ATR-FTIR spectra is proportional to d_p ( $\propto$
$\lambda$ ), as shown in equation S2 of the Supplementary Information. The OH- and H-terminated Si substrates were coated with the epoxy resin and cured using the aforementioned conditions.

The physical state of the CSSGLT isolated QRT was characterized using DSC thermogram analysis (Mettler Toledo DSC 822e; India). 2.93 mg of QRT was weighed separately in standard aluminum pans. A DSC instrument was used for measurement of the melting temperature of QRT with an empty reference aluminum pan. The sample was purged in the DSC with pure dry nitrogen gas which was set at a flow rate of 40 mL min⁻¹. The change in temperature was set at 5 °C min⁻¹, and the heat flow was recorded from 25 °C to 400 °C. Heat flow was measured by comparing the difference in temperature across the sample and the reference. UV-visible spectroscopic analysis was performed using LAB UV3000^plus at room temperature with a quartz cuvette of 1 cm path-length as the sample holder (200–800 nm). IR spectra were recorded in the transmittance range of 4000 to 400 cm⁻¹ on PerkinElmer FTIR spectrometer Frontier using ATR. The ¹H and ¹³C NMR spectra of the QRT were recorded at 500 mHz (¹H NMR) and 125 mHz (13C NMR) using the Bruker (Advance) NMR instrument in DMSO solvent.^{41 (link)1}H NMR (500 MHZ, DMSO-d₆): δ 6.18 (d, 1H, J = 2 Hz), 6.40 (d, 1H, J = 1.5 Hz), 6.87 (d, 1H, J = 9 Hz), 7.52 (dd, 1H, J = 2.5 and 8.5 Hz), and 7.67 (d, 1H, J = 2.5 Hz). ¹³C NMR (125 MHZ, DMSO-d₆): δ 93.32, 98.15, 102.98, 115.03, 115.57, 119.94, 121.92, 135.70, 145.03, 146.77, 147.67, 156.11, 160.69, 163.85, and 175.81.

Preparation of reduction-degradable PAA-g-PEG copolymers was performed by the method reported previously [35 (link)]. Briefly, cystamine bisacrylamide was synthesized by reacting acryloyl chloride with cystamine dihydrochloride in dichloromethane/water. Then, the freshly obtained cystamine bisacrylamide (1.044 g, 4 mmol) was reacted with a mixture of phenethylamine and ethanolamine (total 4 mmol, mol ratio: phenethylamine/ethanolamine = 8/2, 7/3, and 6/4, resp.) at 125°C under Ar atmosphere to acquire PAA containing disulfide linkage. Finally, as an example, amphiphilic PAA-g-PEG (PAA(8:2)-PEG2000) copolymers were obtained by coupling α-carboxy-ω-methoxy polyethyleneglycol (MPEGCOOH, 1.05 g, Mn = 2000, 0.5 mmol of carboxyl) on PAA (0.74 g, phenethylamine/ethanolamine = 8/2, 0.4 mmol of hydroxyl group) using DCC (0.124 g, 0.7 mmol) as coupling agent and DMAP (0.061 g, 0.05 mmol) as catalyst in dry DMSO at room temperature. Following this way, six kinds of amphipathic reduction-degradable PAA-g-PEG copolymers were prepared. The structure and molecule weight of the copolymers were characterized by 1H NMR (VarianUNITY INOVA400) and FT-IR (Perkin Elmer FT-IR spectrometer Frontier).