Two-Dimensional Heterospectral Correlation Analysis of X-ray Photoelectron Spectra and Infrared Spectra for Spin-Coated Films of Biodegradable Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) Copolymers

Abstract

We investigated the thermal behavior of spin-coated films of biodegradable poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P(HB-co-HHx)) copolymers at the molecular level. To better understand details of thermal behavior of spin-coated films of P(HB-co-HHx) copolymers, we applied two-dimensional (2D) correlation analysis to the spectra of P(HB-co-HHx) (HHx = 12.0, 10.0, and 3.8 mol %) copolymers during the heating process from 30 to 150 degrees C as obtained by temperature-dependent infrared-reflection absorption spectroscopy and X-ray photoelectron spectroscopy (XPS). 2D IR and 2D XPS correlation spectra of spin-coated films of P(HB-co-HHx) copolymers clearly revealed the sequence of intensity changes with increasing temperature: an amorphous band increases first and then a band for less ordered secondary crystals decreases before a band for well-ordered primary crystals. Furthermore, the synchronous 2D heterospectral XPS/IR correlation spectrum elucidated the correlation between the IR and XPS bands, confirming their band assignments. The asynchronous 2D heterospectral correlation spectrum revealed the probe-dependent asynchronicity between XPS and IR signals arising from the same species even under identical perturbation conditions because of the different scales of molecular changes probed. It clearly provides a complete interpretation of the phase transition phenomenon of P(HB-co-HHx) copolymers, which could not have been obtained through XPS or IR study alone, and also, the results obtained thereof offer a new insight into the molecular interactions as well observed by two different probes.

Surface Structure of Acrylate Polymer Adhesives

“…SFG is therefore established as a sensitive probe of polymer surface structure. [11][12][13][14][15][16][17][18][19][20][21][22][23][24] However, it is often challenging to separate the effects of orientation from changes in concentration in the SFG signal. In this study we will therefore combine IR absorption and SFG spectroscopy to study the drying process of butyl acrylate PSAs containing varying amounts of acrylic acid.…”

Two-dimensional correlation spectroscopy in polymer study

“…Choi et al demonstrated the details of thermal behavior of spin-coated films of biodegradable poly(3-hydroxybutyrate- co -3-hydroxyhexanoate) or P(HB- co -HHx) (HHx = 12.0, 10.0, 3.8 mol%) copolymers by using 2DCOS (Choi et al, 2010). The temperature-dependent infrared-reflection absorption (IRRAS) spectra of a spin-coated film of P(HB- co -HHx) (HHx = 12.0 mol%) copolymer, which were measured during the heating process, are shown in Figure 2.…”

“…Three possible possibilities in 2D hetero-correlation analysis are hetero-spectral correlation (Kim et al, 2006a; Choi et al, 2010; Katayama et al, 2010; Smirnova et al, 2011; Park et al, 2012; Ryu et al, 2012; Shinzawa et al, 2012), hetero-perturbation (or hybrid) correlation (Wu et al, 2002, 2006), and hetero-sample correlation (Czarnik-Matusewicz et al, 2009; Pi et al, 2010). Among them, 2D hetero-spectral correlation is the most active field in applications of 2D hetero-correlation analysis.…”

“…Choi et al used 2D hetero-spectral correlation between completely different types of spectroscopy, such as IR and X-ray photoelectron spectroscopy (XPS), for the investigation of thermal behavior of biodegradable copolymers under increasing temperature (Choi et al, 2010). The 2D hetero-spectral IR/XPS correlation spectra of spin-coated film of P(HB- co -HHx) copolymer during heating process are shown in Figure 7.…”

Two‐Dimensional Correlation Spectroscopy: New Developments and Applications

“…It is possible to apply 2D heterospectral analysis to the correlation not only between closely related spectroscopic measurement, such as IR and Raman spectra, but also between completely different types of spectroscopic or physical techniques. For example, 2D heterospectral between X-ray photoelectron spectroscopy (XPS) and IR spectroscopy (104) and between wide angle X-ray scattering (WAXS) and IR spectroscopy (109) were used to investigate semi-crystalline copolymers under increasing temperature and to characterize the specific chemical interactions existing in weakly interacting closed-loop block copolymer, respectively. Figure 11 shows heterospectral XPS/IR correlation spectra of spin-coated film of P(HB-co-HHx) copolymer with temperature increases.…”