Techniques for measurement of water vapor sorption and permeation in polymer films

Schult, K. A.; Paul, Donald R

doi:10.1002/(sici)1097-4628(19960912)61:11<1865::aid-app2>3.0.co;2-h

Cited by 50 publications

(19 citation statements)

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“…The rate and extent of the water uptake are determined by a variety of factors, such as temperature, humidity, polymer chemistry, film thickness, pore size and density, and material processing. [1][2][3][4] The structure of the sorbed water is of particular importance, as it can give insight into the interactions between the water and the polymer substrate. Water is a unique penetrant because it interacts strongly with polar groups of the polymer and can form clusters that are confined by the polymer chains.…”

Section: Introductionmentioning

confidence: 99%

“…Among the physical changes that water can induce are plasticization, hygrothermal degradation, swelling, alteration of tensile strength and hardness, and change in net dielectric constant of a film. [2][3][4][5][6] Water can also affect chemical processes in polymers such as the deprotection reaction in photoresists used in the fabrication of electronic circuits. 2,7,8 Poly(t-butoxycarbonylstyrene) (tBOC) 9 and ketal-protected Poly(hydroxystyrene) (KRS-XE) 10 are two important chemically amplified photoresist systems.…”

Section: Introductionmentioning

confidence: 99%

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Fourier transform infrared spectroscopy studies of water-polymer interactions in chemically amplified photoresists

McDonough

Chikán

Kim

et al. 2005

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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ABSTRACT:Fourier-Transform Infrared (FTIR) absorption spectroscopy is implemented to measure the infrared spectrum of water absorbed by the Poly(t-butoxycarbonylstyrene) (tBOC) and the ketal-protected Poly(hydroxystyrene) (KRS-XE) polymer photoresists.The shape and intensity of the OH stretching band of the water spectrum is monitored in a variety of humidity conditions in order to obtain information on the hydrogen-bonding interactions between the water and the polymer chains. The band is deconvoluted into four sub-bands, which represent four types of water molecules in different environments.Because of the hydrophilicity of the polymers studied, a large portion of the sorbed water molecules is believed to be strongly bound to the polar sites of the polymer. The ratios of each type of water are found to be dependent on the humidity conditions to which the sample was exposed. At higher humidities, there is an increase in the fraction of free and weakly-bound water molecules. These findings are used to explain the humidity dependence of the deprotection reaction rates, since certain types of water may slow transport of reactive species within the polymer network.2

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fourier transform infrared spectroscopy studies of water-polymer interactions in chemically amplified photoresists

McDonough

Chikán

Kim

et al. 2005

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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“…The accurate measurement of the permeation rate for water vapor is more difficult than other gases. Complexities arise because of a high heat of vaporization, the adsorption of water onto high‐energy surfaces, and a high solubility in polymers 16. A water‐permeation apparatus was designed and built with these complexities in mind and is detailed elsewhere 16, 17.…”

Section: Methodsmentioning

confidence: 99%

“…Complexities arise because of a high heat of vaporization, the adsorption of water onto high‐energy surfaces, and a high solubility in polymers 16. A water‐permeation apparatus was designed and built with these complexities in mind and is detailed elsewhere 16, 17. This apparatus was modified to accommodate the physical properties of the polymer under investigation 8.…”

Section: Methodsmentioning

confidence: 99%

Forecasting climate variables using a mixed-effect state-space model

2010

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This paper demonstrates the potential advantage of using a linear, mixed-effect state-space model for statistical downscaling of climate variables compared to the frequently used approach of linear regression. This comparison leads to the development of a method for estimation of model parameters using the EM algorithm approach. The model is applied to the prediction of temperature and rainfall statistics at both a sub-tropical and temperate location in Australia. The results indicate that for lead times of 1-10 years this state-space approach is able to predict observed seasonal temperature and rainfall means with substantially greater precision than climatology, multivariate linear regression (MLR) or a standard linear state-space (LSS) approach. The model is seen as a first step in the development of a short-term climate change projection system that will utilise both historical climate data as well as dynamically derived mean climate change projection information obtained from global climate models (GCMs).

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“…Water is a complex penetrant, and because of its polarity and ability to form hydrogen bonds, it may interact strongly with itself or with the polymer. Water also has a tendency to cluster and to plasticize the polymer matrix 30. To characterize the polymer/water interaction, we apply Flory–Rehner theory31 to correlate the equilibrium data for each solvent–polymer system.…”

Section: Introductionmentioning

confidence: 99%

Sorption kinetics and equilibrium uptake for water vapor in soft‐contact‐lens hydrogels

Weinmüller

Langel

Fornasiero

et al. 2006

J Biomedical Materials Res

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A gravimetric-sorption technique was used to obtain kinetic and equilibrium adsorption/desorption data for water vapor in four different soft-contact-lens (SCL) polymers at 35 degrees C. The SCL materials are a conventional hydrogel (polymacon) with a low water content at saturation (<50 wt %); two conventional hydrogels (hilafilcon A and alphafilcon A) with a high water content at saturation (>50 wt %); and a siloxane hydrogel (balafilcon A). Absorption and desorption equilibrium isotherms (water activity versus water weight fraction) overlap at high water contents, whereas significant hysteresis is observed at low water contents. The hysteresis loop is likely due to trapping of water in the polymer during the desorption process because of a rubber-to-glass transition of the SCL-film surfaces. Sorption data were interpreted using Flory-Rehner theory. The positive Zimm and Lundberg cluster function suggests that water tends to cluster in these SCL materials, except at very low water content. For polymacon and hilafilcon A, Fickian diffusion is observed for all activities for both water sorption and desorption. However, for alphafilcon A and balafilcon A, non-Fickian features appear at intermediate/low activities, in particular during water desorption, suggesting coupling of the diffusion process with polymer-matrix relaxation. The diffusion coefficient increases significantly with water concentration for polymacon and hilafilcon A (from approximately 0.3 x 10(-8) to 4.0 x 10(-8) cm2/s) because of augmented mixture free volume induced by water sorption, whereas a more complex composition dependence is observed for alphafilcon A and balafilcon A probably as consequence of a combined effect of polymer relaxation, plasticization, and water clustering.

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Techniques for measurement of water vapor sorption and permeation in polymer films

Cited by 50 publications

References 3 publications

Fourier transform infrared spectroscopy studies of water-polymer interactions in chemically amplified photoresists

Fourier transform infrared spectroscopy studies of water-polymer interactions in chemically amplified photoresists

Forecasting climate variables using a mixed-effect state-space model

Sorption kinetics and equilibrium uptake for water vapor in soft‐contact‐lens hydrogels

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