Figure 3 - uploaded by Luis G. Rosa
Content may be subject to copyright.
HDO from D2O and HDO from H2O production from absorbed heavy water and water are compared. Panels a and b show the integrated intensity of the water (b) and heavy water (9) and the corresponding HDO (O) intensity abstracted from the thermal desoprtion peak associated with absorbed water (desorbing at approximately 375 K) as a function of water or heavy water exposure to P(VDF-TrFE) at 120-135 K. Panels b and d show the coverage of the HDO/H 2O and HDO/D2O ratios for alternating water and heavy water thermal desorption experiments of as function of exposure of water and heavy water, respectively, to P(VDF-TrFE) at 120-135 K. The insets show the mass spectra of H 2O and D2O, i.e., no HDO (mass 19) without isotopic exchange with the P(VDF-TrFE).
Source publication
For both water and heavy water adsorption and absorption on crystalline poly(vinylidene fluoride with trifluoroethylene (30%)), P(VDF-TrFE 70:30), two distinctly different adsorption sites have been identified by thermal desorption spectroscopy. One adsorbed water species resembles ice and there is also an absorbed water species that interacts more...
Contexts in source publication
Context 1
... desorption experiments were undertaken on a slightly thinner P(VDF-TrFE) film of nominally 25 monolayers (to lower slightly the temperature of the absorbed water thermal desorption peak) and alternating H 2 O and D 2 O (the alternation of H 2 O and D 2 O experiments is meant to prevent excessive deuteration or rehydrogenation). Desorption spectra were measured for the HDO (o) and H 2 O (b) masses simultaneously, after a H 2 O exposure to P(VDF-TrFE) at 120-135 K, and the HDO (o) and D 2 O (b) masses simultaneously after D 2 O exposure to P(VDF-TrFE) at 120-135 K, plotted as intensities in Figure 3, panels a and c, respectively. The thermal desorption intensities for the bulk absorbed H 2 O and D 2 O phase that desorbs from P(VDF-TrFE) at higher temperatures (above 300 K) are plotted in Figure 3a,c. ...
Context 2
... spectra were measured for the HDO (o) and H 2 O (b) masses simultaneously, after a H 2 O exposure to P(VDF-TrFE) at 120-135 K, and the HDO (o) and D 2 O (b) masses simultaneously after D 2 O exposure to P(VDF-TrFE) at 120-135 K, plotted as intensities in Figure 3, panels a and c, respectively. The thermal desorption intensities for the bulk absorbed H 2 O and D 2 O phase that desorbs from P(VDF-TrFE) at higher temperatures (above 300 K) are plotted in Figure 3a,c. Panels b and d in Figure 3 show Figure 3, this more strongly bound water and heavy water species (absorbed water and heavy water) are associated with significant HDO production, i.e., significant isotopic exchange. ...
Context 3
... thermal desorption intensities for the bulk absorbed H 2 O and D 2 O phase that desorbs from P(VDF-TrFE) at higher temperatures (above 300 K) are plotted in Figure 3a,c. Panels b and d in Figure 3 show Figure 3, this more strongly bound water and heavy water species (absorbed water and heavy water) are associated with significant HDO production, i.e., significant isotopic exchange. ...
Context 4
... thermal desorption intensities for the bulk absorbed H 2 O and D 2 O phase that desorbs from P(VDF-TrFE) at higher temperatures (above 300 K) are plotted in Figure 3a,c. Panels b and d in Figure 3 show Figure 3, this more strongly bound water and heavy water species (absorbed water and heavy water) are associated with significant HDO production, i.e., significant isotopic exchange. ...
Context 5
... is significant H/D exchange between absorbed heavy water and the crystalline copolymer poly(vinylidene fluoride with trifluoroethylene (30%)), P(VDF-TrFE 70:30), as summarized in Figure 3. This work also illuminates a method for the deuteration of partially fluorinated polymers (and no doubt many other polymers as well) by exploiting the efficient isotopic exchange between heavy water and the crystalline copolymer poly(vinylidene fluoride with trifluoroethylene (30%)), P(VDFTrFE 70:30), in other like polymers. ...
Similar publications
Water adsorption and absorption on crystalline polyvinylidene fluoride with 30% trifluoroethylene, P(VDF-TrFE, 70:30), was examined by thermal desorption spectroscopy. Two distinctly different water adsorption sites are identified: one adsorbed species that resembles ice and another species that interacts more strongly with the polymer thin film. T...
Ferroelectric crystalline copolymer films of vinylidene fluoride with trifluoroethylene (70%:30%) strongly interact with the dipoles of adsorbed and absorbed water molecules. This interaction can be probed with laser-assisted thermal desorption techniques. The UV light enhancement of water desorption is strongly light polarization dependent. The el...
Citations
... Six rectangular pieces of 2 cm x 1.5 cm were obtained; these were cleaned to eliminate organic contamination, sonicated in acetone, and then dried. Once dried, the pieces were sonicated in ethanol and finally dried with nitrogen gas [96][97][98][99][100]. ...
... [277]/99 [20][21][22][23]. Water absorption is seen to result in lattice strain (a local distortion of the polymer chains) for water absorbed in the copolymers poly(vinylidene fluoride-trifluoroethylene) and the dipole ordered polymer poly(methylvinylidene cyanide), recently observed. ...
Herein we compare the water absorption/ adsorption on three different polymer films: the ferroelectric co-polymer poly(vinylidene fluoride with trifluoroethylene) P(VDF-TrFE), the strongly dipole oriented polymer poly(methyl vinylidene cyanide) (PMVC) [1] and the dipole oriented poly(methyl methacrylate) PMMA. We investigate the dipole-dipole interaction of the water molecule and the ferroelectric/ dipole oriented polymer films and we propose that the dipole interactions may affect the surface chemistry at these polymer surfaces. Surface dipoles can affect the binding site of water species adsorbed at the surface and sterically hinder or enhance desorption of adsorbed and absorbed water.[4pt] [1] Dowben, P.A., Rosa, Luis G., Ilie, C.C., Zeitschrift f"ur Physikalische Chemie 222 (2008) 755-778.
... [277]/99 [20][21][22][23]. Water absorption is seen to result in lattice strain (a local distortion of the polymer chains) for water absorbed in the copolymers poly(vinylidene fluoride-trifluoroethylene) and the dipole ordered polymer poly(methylvinylidene cyanide), recently observed. ...
We find evidence for lattice swelling and contraction due to water on absorption on P(VDFTrFE)
and PMVC respectively. The absorption of water is associated with strong dipolar
interactions with the substrate leading to intake of water as demonstrate by desorption
experiments and subsequently lattice swelling or contractions due to water absorption.
We investigate over a period of a 500 hours the effect of relative humidity (RH) on the retention loss in ferroelectric P(VDF-TrFE) thin films by using piezoresponse force microscopy (PFM). When the copolymer films are exposed to more water molecules, more domain reversal is observed, especially in upward domains. Interestingly, the retention loss behavior based on a stretched exponential model can be distinctly classified depending on the RH conditions. We conjecture that the absorption and the desorption of water molecules in the P(VDF-TrFE) polymers have a great influence on the reversal of ferroelectric domains.
Polyvinylidene fluoride-trifluoroethylene (P(VDF-TrFE)) copolymers, also called Nobel polymers due to their ferroelectric, piezoelectric, and pyroelectric properties, possess non-lineal optical properties and low acoustic impedance that pair with water and living tissue (i.e. are biocompatible). These qualities make them promising for multiple electronic applications. In this paper we explore the effects of applying a shearing force on copolymer of Polyvinylidene Fluoride with Trifluoroethylene (P(VDF-TrFE) thin film has been studied. A shearing technique was used to induce stress on the film, which produced an improvement in crystallization and grain size.
The absorption of water in Langmuir–Blodgett films of ferroelectric copolymers of polyvinylidene fluoride with trifluoroethylene is shown to depend upon the film thickness. This water absorption can have a profound effect on the dielectric properties of the copolymer films.
We compare the interactions of water with the ferroelectric copolymer poly(vinylidene fluoride (PVDF) - trifluoroethylene (TrFE)) and poly(methylvinylidenecyanide) (PMCV), a strongly dipole ordered polymer. At the microscopic scale, dipole interactions matter and affect the surface chemistry at these polymer surfaces, its does lattice strain caused by water absorption. Light polarization dependent photo-assisted thermal desorption helps demonstrate that water desorption from surface and bulk can be influenced by the formation of electronic metastable states. Changes in local dipole orientation and the formation of long lived metastable states affect the strength of the coupling between the dipoles of water molecules and the dipoles of the copolymer poly(vinylidene fluoride - trifluoroethylene) but these effects were not observed for poly(methylvinylidenecyanide).
We compare water adsorption and desorption on ferroelectric copolymer poly(vinylidene fluoride-trifluoroethylene), and the dipole ordered polymer poly(methylvinylidene cyanide). The angle-resolved thermal desorption spectra prove that the absorbed water species interacts more strongly with poly(vinylidene fluoride-trifluoroethylene) than with poly(methylvinylidene cyanide). The angle resolved thermal desorption spectra shows large deviations from the cosine distribution for light illuminated poly(vinylidene fluoride-trifluoroethylene). Water desorption from poly(methylvinylidene cyanide) deviates from the cosine distribution without illumination.
We have investigated the chemisorption of two isomers of diiodobenzene on the molecular ferroelectric copolymer poly(vinylidene fluoride) with trifluoroethylene (70:30) as a function of the polymeric ferroelectric domain orientation. We find that the 1,4-p-diiodobenzene adsorption at 150 K strongly favors a positive ferroelectric domain orientation while the 1,2-o-diiodobenzene adsorption at 150 K strongly favors a negative ferroelectric domain orientation. Both polar and nonpolar adsorbates are influenced by the substrate dipole direction. Because a nonpolar isomer is also affected by the surface dipole direction, and hence the surface chemical termination, it is clear that surface chemistry and not simply surface dipoles matter in the chemisorption process.
Reversible bromoform adsorption on crystalline polyvinylidene fluoride with 30% of trifluoroethylene, P(VDF-TrFE 70:30) was examined by photoemission and inverse photoemission spectroscopies. The adsorption of bromoform on this polymer surface is associative and reversible. Molecular bromoform adsorption appears to be an activated process at 120 K with enhanced adsorption following the initial adsorption of bromoform. Strong intermolecular interactions are also implicated in the presence of a weak shake off or screened photoemission final state, whose intensity scales with the unscreened photoemission final state. (C) 2008 Elsevier B.V. All rights reserved.
