2.4.2. Infrared (IR) Analysis

The variations in chemical structures of the coating during the test were monitored by IR spectra on FT-IR spectroscopy (NEXUS 670, Nicolet Instrument Corporation, Madison, WI, USA). The quantitative analysis of the structural groups was calculated based on the changes in optical density of their characteristic absorption by the method we reported previously [3,5,7].

#### 2.4.3. Ultraviolet-Visible (UV-Vis) Analysis

The UV-Vis absorption spectra of the coatings were analyzed on UV-Vis spectrophotometer (GBC, CINTRA 40, Austin, TX, USA) and performed on the samples which were examined by IR analysis.
