Understanding the fingerprint region in the infra-red spectra of perfluorinated ionomer membranes and corresponding model compounds: Experiments and theoretical calculations

Danilczuk, Marek; Lu, Lin; Schlick, Shulamith; Hamrock, Steven J.; Schaberg, Mark S.

doi:10.1016/j.jpowsour.2011.05.067

Cited by 56 publications

(108 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…With the loss of water from NAFIONt membranes the formation of acidic SO 3 H was reported at 1415 cm À1 in agreement with our NAFIONt heating measurements. 34,58 A similar feature at 1431 cm À1 in (CF 3 SO 2 ) 2 NH was attributed to the antisymmetric SQO combined with H-NS stretching vibration of the sulfonyl imide group. 53,54 Based on the above literature findings and a close match in the position and band shape of the acidic SO 3 H band of our NAFIONt measurements to the shoulder peak at B1421 cm À1 in PFIA we tentatively assign the doublet peaks at 1450 and 1439 cm À1 to the antisymmetric SQO of the acidic sulfonyl imide group and the band at B1421 cm À1 to the antisymmetric SQO to the acidic SO 3 H form.…”

Section: Acidic Formsmentioning

confidence: 87%

“…The shoulder at 825 cm À1 can be assigned to the symmetric stretching mode of the COC group of the neutralized form. 34 Analogous to the (CF 3 SO 2 ) 2 NH molecule a 868 cm À1 band in PFIA can be assigned to the asymmetric stretch of the SNS bond. 54 A small broad peak at 933 cm À1 in PFIA which appears at the later stage and together with the appearance of the shoulder at 1421 cm À1 is similar to the broad peak at 896 cm À1 in dehydrated NAFIONt membranes.…”

Section: Acidic Formsmentioning

confidence: 99%

“…12,[30][31][32][33][34][35] We applied Fourier transform infrared (FTIR) spectroscopy to follow the changes in H 2 O saturated PFIA membranes during heating to high temperatures under a range of humidity conditions. These in situ measurements in conjunction with 2D correlation analysis allowed the full assignment of bands in the mid infrared region and further provided information on the microstructural changes occurring during heating and cooling processes.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Infrared dynamics study of thermally treated perfluoroimide acid proton exchange membranes

Puškar

Ritter

Schade

et al. 2017

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

The temperature induced dehydration process of the 3M Brand perfluoroimide acid (PFIA), an advanced proton exchange membrane for fuel cells, was studied by in situ infrared spectroscopy to understand proton transport processes under conditions of low hydration levels. A comprehensive assignment of the vibrational bands of PFIA in the mid infrared region is provided. Investigation of the kinetics in conjunction with 2D correlation spectroscopy methods revealed the sequential process of the hydration and dehydration in a conclusive model. The results indicate that at a lower water content the sulfonate group of the PFIA side chain is preferentially ionised and involved in a hydrogen bonding structure with the sulfonyl imide acid group, until a sufficient amount of water is present to ionise the second ionic site. Comparison to the well-understood NAFION™ membrane revealed that under low humidity conditions a higher amount of water is retained in PFIA in a state most similar to liquid water. The results contribute to a better understanding of water retention capability and thus proton conductivity under high-temperature and low-humidity conditions.

show abstract

Section: Acidic Formsmentioning

confidence: 87%

Section: Acidic Formsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Infrared dynamics study of thermally treated perfluoroimide acid proton exchange membranes

Puškar

Ritter

Schade

et al. 2017

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…Nafion has been the membrane of choice for PEMFCs due to its stability and relatively high ionic conductivity, under conditions targeted for low temperature PEMFC operation. 1,3,12,[16][17][18][19][20][21][22][23][24][25][26] Although extensively studied 11,26 , there is still debate about the structure of ion conducting and hydrophobic framework regions and nanoscale properties that affect strength and flexibility 11,[27][28][29] .…”

Section: Introductionmentioning

confidence: 99%

Electronic Structure and Vibrational Mode Study of Nafion Membrane Interfacial Water Interactions

Kabrane

Aquino

2014

J. Phys. Chem. A

View full text Add to dashboard Cite

The structural, energetic, and mid-infrared spectral properties of water clusters interacting with a model perfluorosulfonate (Nafion) ionomer segment have been investigated by means of quantum chemical calculations. Density functional theory calculations were conducted to model interfacial water condensed in pores and channels of Nafion and helped shedding light on the structural and vibrational properties of hydrated Nafion membranes. The computational models consisted of a sodium counterion, the Nafion ionomer, and a cluster of water molecules positioned in three different regions of the ionomer. The orientations of the water molecules in the vicinity of the ionomer were examined to understand the appearance of O-H stretching bands that deviated from the typical bulk water values as well as the appearance of multiple free O-H stretching bands. The calculations revealed insights into the structure, orientation, and energetics of Nafion and water clusters in and around the membrane interface; the results show that hydrogen atoms at the water-ionomer interface hydrogen bond to the hydrophilic sulfonate group as well as to the hydrophobic fluorinated backbone.

show abstract

“…The physically adsorbed water is removed and only water bound in form of ions is present. More interestingly, the SO 3 -stretching vibration at 1060 cm -1 is systematically shifted to higher wave numbers in the dried out PEM matrix (30,31). This shift can be observed in the ATR and the transmission spectra.…”

Section: Depth Informationmentioning

confidence: 78%

Surface Analytical Methods for the Development of Electrochemical Components of Polymer Electrolyte Fuel Cells

2013

View full text Add to dashboard Cite

A comprehensive overview of infrared absorption, Raman, and Xray photoemission spectroscopy and their application in fuel cell research is given in this paper. Based on these ex-situ spectroscopic techniques a set of methods addressing the specific problems in the development of polymer electrolyte fuel cells are discussed and compared, regarding multi scale chemical characterizations and the analytics of outer surfaces, inner surfaces and buried layers. It is shown, that a combination of complementary methods is necessary to gather a comprehensive view of the occurring processes and mechanisms.

show abstract

Understanding the fingerprint region in the infra-red spectra of perfluorinated ionomer membranes and corresponding model compounds: Experiments and theoretical calculations

Cited by 56 publications

References 33 publications

Infrared dynamics study of thermally treated perfluoroimide acid proton exchange membranes

Infrared dynamics study of thermally treated perfluoroimide acid proton exchange membranes

Electronic Structure and Vibrational Mode Study of Nafion Membrane Interfacial Water Interactions

Surface Analytical Methods for the Development of Electrochemical Components of Polymer Electrolyte Fuel Cells

Contact Info

Product

Resources

About