Qms 403 d aeolos ms

A field
emission scanning electron microscope (FE-SEM, JSM-7610F) was used
to visualize the thickness and morphology of the obtained TFCs. Both
surface and cross-section images were acquired. Samples were prepared
by immersion in liquid nitrogen for 5 min and carefully fractured
to reveal the complete cross-section. Subsequently, all samples were
mounted on an FE-SEM holder using a double-sided carbon tape. Fourier
transform infrared spectroscopy in attenuated total reflectance mode
(FTIR-ATR, PerkinElmer Spectrum Two) was used to characterize the
free-standing film product. Spectra were averaged over 16 scans with
a resolution of 4 cm^–1 over a wavenumber range of
400–4000 cm^–1. The elemental composition
of synthesized free-standing films was measured with X-ray fluorescence
(XRF) (S8 Tiger, Bruker) and CN elemental analysis (FLASH 2000 series
analyzer). The thermal stability of the materials was measured by
heating a fixed amount of sample (10 mg) on a heating stage under
an inert nitrogen atmosphere at a heating rate of 10 °C min^–1 using a thermo gravimetric analyzer (TGA, STA 449
F3 Jupiler, Netzsch) in combination with a mass spectrometer (MS,
QMS 403 D Aeolos MS, Netzsch). Ultraviolet–visible (UV–vis)
spectra of THB and MDHB solutions with different concentrations of
KOH were recorded on a PerkinElmer λ12 UV–vis spectrophotometer.