Glass Transition Temperature and Conformational Changes of Poly(methyl methacrylate) Thin Films Determined by a Two-Dimensional Map Representation of Temperature-Dependent Reflection−Absorption FTIR Spectra

Abstract

Temperature-dependent reflection−absorption Fourier transform infrared spectra of poly(methyl methacrylate) (PMMA) thin films were measured. From these spectra, two-dimensional (2D) maps of the first derivative of the absorbance with respect to temperature over the space of wavenumber and temperature were constructed. These maps were used to determine the glass transition temperature and to investigate the subtle temperature dependence of the population of trans and gauche conformers in three PMMA thin films with different stereoregularities. The glass transition temperatures determined from the 2D maps for isotactic, syndiotactic, and atactic PMMA thin films were approximately 61, 111, and 106 °C, respectively. Calculations of the fraction of gauche conformation from the conformational energy showed an abrupt increase in the population of the gauche conformer above the glass transition temperature. The temperature dependence of the fraction of gauche conformation was well reflected in our 2D maps. Furthermore, it was found that molecular reorganization of PMMA occurs even below the glass transition temperature.

Advances in two-dimensional correlation spectroscopy

“…For example, Jung and coworkers [102,103] reported the use of such direct 2D data plots. Temperature scan of a LangmuirBlodgett film of poly(tert-butyl methacrylate) were carried out.…”

Suitability of PEG/PMMA-based metal injection moulding feedstock: an experimental study

“…Therefore, upon crystallization, it undergoes a significant volumetric shrinkage [17,18]. In comparison to PEG, PMMA is an amorphous polymer having glass transition temperature of 106°C [19]. In the PEG/PMMA blends, solidification leads to segregation of PEG, concomitant of simultaneous rejection of the amorphous component [20].…”

Photogeneration of Silver Nanoparticle Facilitated by Pluronic F127 Surfactant in Ethanolic Solution

“…The two dimensional mapping technique, is a simple mathematical treatment on a data set of spectra, A(x,y), where x and y are variables, has been presented by Shin et al [28] The x variable is usually wavenumber and y variable can be temperature, [28] UV exposure energy, [29] and so on. This technique is based on taking the first derivative of absorption with respect to the related variable, d(x,y)=dy, and then plotting the first derivative as a function of independent variables x and y.…”

“…This technique is based on taking the first derivative of absorption with respect to the related variable, d(x,y)=dy, and then plotting the first derivative as a function of independent variables x and y. [28,29] Resolving the overlapped bands and also interpret the complex spectra changes during photoreactions induced by UV light irradiation is possible by using of two-dimensional map technique. [29] The two-dimensional map technique was used successfully in various spectroscopy studies such as determination the glass transition temperature of poly (methyl methacrylate) thin film, [28] study of photoreaction in a nanoscale film, [29] and study the thermal behaviour of a copolymer.…”

“…[28,29] Resolving the overlapped bands and also interpret the complex spectra changes during photoreactions induced by UV light irradiation is possible by using of two-dimensional map technique. [29] The two-dimensional map technique was used successfully in various spectroscopy studies such as determination the glass transition temperature of poly (methyl methacrylate) thin film, [28] study of photoreaction in a nanoscale film, [29] and study the thermal behaviour of a copolymer. [30] In our recent work we have successfully used the two-dimensional map technique to determine the switching time from nucleation to growth processes of Ag NPs formation.…”