The IR spectra of solutions of a perfluorinated polyamide in different solvents are analyzed in t... more The IR spectra of solutions of a perfluorinated polyamide in different solvents are analyzed in the spectral range of "free NH" stretching modes, in order to study the effects of hydrogen bonding in determining the unusual spectral behaviour observed for these systems. The presence of different bands in the spectral range associated to NH bonds with the H atom not involved in hydrogen bonding and their evolution with the polymer concentration has shown that free NH bonds have a different nature depending on the occurrence of hydrogen bonding on neighbour atoms and on the configuration of the molecular complexes in which they are involved. These differences have been interpreted on the basis of DFT (B3LYP/6-311þþG**) computations on suitable molecular models that allowed a qualitative and quantitative rationalization of the chemicalephysical effects involved. The computational analysis points out the subtle intramolecular and intermolecular vibrational effects occurring in these systems and brings to an interpretation and assignment of the IR spectra which goes over the interpretations usually adopted when dealing with the vibrational spectroscopy of hydrogen bonded polymers and molecules.
High-energy particle accelerator UHV systems subjected to energetic charged particle or photon bo... more High-energy particle accelerator UHV systems subjected to energetic charged particle or photon bombardment are particularly sensitive to surface contamination. Well-established cleaning procedures employing solvents such as Freon and perchloroethylene to prepare vacuum system components have been used at CERN for many years. The recently adopted legislation which prescribes or strongly limits the use of some chemicals has led CERN to undertake a qualification programme using electron stimulated desorption, Auger spectroscopy and radioactive tracers to compare the cleaning efficiency of a wide range of alternative cleaning agents.
Amorphous fluorinated optical polymers, characterized by high transparency in the visible and nea... more Amorphous fluorinated optical polymers, characterized by high transparency in the visible and near infrared spectra, high glass transition temperature and very good resistance to chemical environment, have been developed by co-polymerisation of tetrafluoroethylene (TFE) and 2,2,4-trifluoro-5-trifluoromethoxy-1,3-dioxole (TTD). In this work we study at molecular level the effect of the introduction of the bulky TTD unit in a perfluoroalkyl chain.
Modern integrated circuits require insulating materials with a dielectric constant as low as poss... more Modern integrated circuits require insulating materials with a dielectric constant as low as possible in order to obtain device speed improvements through lower RC delay.We have investigated the electrical and structural properties of PTFE thin films obtained from Algoflons-PTFE nanoemulsions, via spin coating deposition, followed by sintering. Films as thin as 160 nm with dielectric strength better than 4 MV/cm
Radiative transfer modelling of AGB circumstellar envelopes is applied to a sample of AGB stars p... more Radiative transfer modelling of AGB circumstellar envelopes is applied to a sample of AGB stars previously observed with the mid-IR imaging camera TIRCAM (Busso et al. 1996: Paper I). We present the results of our simulations, aimed at deriving the physical parameters of the envelope, such as its optical depth, radial thermal structure, mass loss and dust-to-gas mass ratio. The chemical composition of the dust in the observed envelopes is discussed. The ability of different sets of dust opacities to fit the mid-infrared spectra is evaluated. The hypothesis of dust grain aging and annealing in O-rich envelopes is considered in order to explain an apparent inadequacy of the availabe opacities to describe the variety of observed spectra, as previously noted by other authors. Various possible origins of the discrepancies are discussed, together with their consequences on the dust grain formation processes.
... These poly-mers are used in high-tech applications like high vacuum technology, speciallubric... more ... These poly-mers are used in high-tech applications like high vacuum technology, speciallubrica-tion, aerospace and electronic industries, etc. ... [6] David J. Carre`, Jonathan A. Markowitz, ''The reac-tion of Perfluoropolyalkyether Oil with FeF3, AlF3 and ...
The IR spectra of solutions of a perfluorinated polyamide in different solvents are analyzed in t... more The IR spectra of solutions of a perfluorinated polyamide in different solvents are analyzed in the spectral range of "free NH" stretching modes, in order to study the effects of hydrogen bonding in determining the unusual spectral behaviour observed for these systems. The presence of different bands in the spectral range associated to NH bonds with the H atom not involved in hydrogen bonding and their evolution with the polymer concentration has shown that free NH bonds have a different nature depending on the occurrence of hydrogen bonding on neighbour atoms and on the configuration of the molecular complexes in which they are involved. These differences have been interpreted on the basis of DFT (B3LYP/6-311þþG**) computations on suitable molecular models that allowed a qualitative and quantitative rationalization of the chemicalephysical effects involved. The computational analysis points out the subtle intramolecular and intermolecular vibrational effects occurring in these systems and brings to an interpretation and assignment of the IR spectra which goes over the interpretations usually adopted when dealing with the vibrational spectroscopy of hydrogen bonded polymers and molecules.
High-energy particle accelerator UHV systems subjected to energetic charged particle or photon bo... more High-energy particle accelerator UHV systems subjected to energetic charged particle or photon bombardment are particularly sensitive to surface contamination. Well-established cleaning procedures employing solvents such as Freon and perchloroethylene to prepare vacuum system components have been used at CERN for many years. The recently adopted legislation which prescribes or strongly limits the use of some chemicals has led CERN to undertake a qualification programme using electron stimulated desorption, Auger spectroscopy and radioactive tracers to compare the cleaning efficiency of a wide range of alternative cleaning agents.
Amorphous fluorinated optical polymers, characterized by high transparency in the visible and nea... more Amorphous fluorinated optical polymers, characterized by high transparency in the visible and near infrared spectra, high glass transition temperature and very good resistance to chemical environment, have been developed by co-polymerisation of tetrafluoroethylene (TFE) and 2,2,4-trifluoro-5-trifluoromethoxy-1,3-dioxole (TTD). In this work we study at molecular level the effect of the introduction of the bulky TTD unit in a perfluoroalkyl chain.
Modern integrated circuits require insulating materials with a dielectric constant as low as poss... more Modern integrated circuits require insulating materials with a dielectric constant as low as possible in order to obtain device speed improvements through lower RC delay.We have investigated the electrical and structural properties of PTFE thin films obtained from Algoflons-PTFE nanoemulsions, via spin coating deposition, followed by sintering. Films as thin as 160 nm with dielectric strength better than 4 MV/cm
Radiative transfer modelling of AGB circumstellar envelopes is applied to a sample of AGB stars p... more Radiative transfer modelling of AGB circumstellar envelopes is applied to a sample of AGB stars previously observed with the mid-IR imaging camera TIRCAM (Busso et al. 1996: Paper I). We present the results of our simulations, aimed at deriving the physical parameters of the envelope, such as its optical depth, radial thermal structure, mass loss and dust-to-gas mass ratio. The chemical composition of the dust in the observed envelopes is discussed. The ability of different sets of dust opacities to fit the mid-infrared spectra is evaluated. The hypothesis of dust grain aging and annealing in O-rich envelopes is considered in order to explain an apparent inadequacy of the availabe opacities to describe the variety of observed spectra, as previously noted by other authors. Various possible origins of the discrepancies are discussed, together with their consequences on the dust grain formation processes.
... These poly-mers are used in high-tech applications like high vacuum technology, speciallubric... more ... These poly-mers are used in high-tech applications like high vacuum technology, speciallubrica-tion, aerospace and electronic industries, etc. ... [6] David J. Carre`, Jonathan A. Markowitz, ''The reac-tion of Perfluoropolyalkyether Oil with FeF3, AlF3 and ...
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