Infrared ellipsometry of interdiffusion in thin films of miscible polymers

Abstract

A new application of infrared ellipsometry is reported. Specifically, the interdiffusion between thin films of miscible polymers (poly(methyl methacrylate) and poly(vinylidene fluoride)) is detected in a non-invasive measurement. A novel technique of data analysis for interdiffusion was developed and is described. The validity of the approach is supported by simulations of diffusion in a bilayer. The onset of extensive interdiffusion over a time period of 15 min. occurs at a temperature of 160 ºC. At a temperature of 190 °C, the data show that complete mixing of a bilayer (850 nm thick) occurs within 30 s, which is consistent with previously reported values of the mutual diffusion coefficient. IR ellipsometry is non-invasive, applicable at elevated temperatures, and relatively fast and sensitive. Although in these measurements, it was unable to determine a concentration profile at the interface, IR ellipsometry was successfully used to detect when interdiffusion had occurred. Hence, it is a useful means for screening polymer pairs for miscibility. Running head: Infrared Ellipsometry of Polymer Interdiffusion

Analysis of Organic Films and Interfacial Layers by Infrared Spectroscopic Ellipsometry

“…Increasing potential of IRSE is foreseen for the structural investigations of ultra thin films and organic multilayers in nanotechnology and polymer science. This is emphasized by recent works showing the potential of the ellipsometric technique for studies of mixing in miscible polymers 60,62 and the variation of composition in mixed polymer brushes. 61 Furthermore, the optical constants as determined by infrared ellipsometry could be used for interpretation of spectra from other techniques (as for example scanning near field optical microscopy, see Ref.…”

“…This potential has been addressed in three recent publications. [60][61][62] In Fig. 9 the characterization of the mixing process in thin double layers of poly(n-butyl methacrylate) (PnBMA) and poly(vinyl chloride) (PVC) on gold from Ref.…”

Spectroscopic Ellipsometry of Mucin Layers on an Amphiphilic Diblock Copolymer Surface

“…This noninvasive technique can study thin multi-layers with much greater sensitivity than can be obtained from transmission spectroscopy, 22 but with greater penetration depths than afforded by internal reflection spectroscopy yielding information on thickness. 19 It has been applied with good success to studies of interfacial chemistry 23 and bonding, 24,25 to polymer orientation, 26 to interdiffusion in polymer bilayers, 27,28 and to polymer brushes. 29 There are a few examples of applications of IR ellipsometry to the study of biological molecules in thin films and at interfaces, 19,[30][31][32] but, until now, the technique has not been applied to detailed studies of biomolecular interfacial bonding and conformation.…”

How Chain Intermixing Dictates the Polymorphism of PVDF in Poly(vinylidene fluoride)/Polymethylmethacrylate Binary System during Recrystallization: A Comparative Study on Core–Shell Particles and Latex Blend

“…Generally, although the core–shell morphology of PVDF@PMMA nanoparticle could be confirmed by an electron microscope, the inner microstructure was very difficult to be exactly determined, however, considering the overall reaction process, the structure was mainly influenced by two factors: (1) the distribution of swollen MMA monomers along the radial direction inside the PVDF core; and (2) the inter-diffusion of PVDF and the polymerized PMMA. According to previous research, the inter-diffusion was mainly controlled by the diffusion of PMMA into PVDF when the temperature was below the melting point of PVDF [23,24]. Therefore, under the reaction temperature (75 °C, below the glass transition temperature of PMMA), the diffusion of PMMA into PVDF should be extremely small and could be negligible.…”