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In Situ Monitoring the Molecular Diffusion Process in Graphene Oxide Membranes by ATR-FTIR Spectroscopy Wenji Guo, Jianbo Chen, Suqin Sun, and Qun Zhou J. Phys. Chem. C, Just Accepted Manuscript • DOI: 10.1021/acs.jpcc.6b02616 • Publication Date (Web): 18 Mar 2016 Downloaded from http://pubs.acs.org on March 20, 2016

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The Journal of Physical Chemistry

In situ Monitoring the Molecular Diffusion Process in Graphene Oxide Membranes by ATR-FTIR Spectroscopy Wenji Guo, Jianbo Chen, Suqin Sun and Qun Zhou∗

Department of Chemistry, Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education), Tsinghua University, Beijing 100084, China.

AUTHOR INFORMATION Corresponding Author * E-mail: [email protected] Tel: (+86)10 6278 1689

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ABSTRACT Graphene Oxide (GO) membranes have been widely explored for molecular separation, but the molecular diffusion behaviour inside GO membranes and the interaction between the diffusates and GO sheets during diffusion are still unclear and rarely studied. In this paper, the time-dependent attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy was used for the first time to in situ monitor the diffusion processes of several typical organic solvents through GO membranes. The diffusion coefficients of the solvents and the evolution of molecular interaction during diffusion were investigated. The diffusion coefficients of the solvents decrease with the increase of their interaction with the oxygen-containing functional groups on GO sheets. In addition, when diffusing into GO membranes, solvent molecules exhibit a different aggregation form compared with their bulk states. Time-dependent ATR-FTIR spectroscopy can be an efficient and powerful technique to explore the molecular diffusion mechanism in GO membranes.

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INTRODUCTION Because of the atomic thickness, high mechanical strength, and chemical inertness, graphene and its derivatives have been recently recognized as an excellent platform for developing high-performance separation membranes.1 As the oxidation state of graphene, graphene oxide (GO) can be easily fabricated by a low-cost modified Hummers method.2−5 Being rich in oxygen-containing functional groups, GO shows good dispersibility and processibility in water. In recent years, many studies have explored the applications of GO membranes in molecular separation, such as gas separation,6−8 water desalination,9−10 and pervaporation11−13. However, most of previous researches only focused on improving the separation performance,14−16 while the diffusion behaviour and molecular interaction between the diffusate and GO membranes are still unclear and rarely studied. Understanding the mechanism of the molecular diffusion process can be very helpful to improve the separation performance of GO membranes. Therefore, an in situ method is urgently needed to monitor the diffusion behaviour of the diffusate inside GO membranes and reveal the interactions between the diffusate and GO sheets at real time. Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy is a straightforward technique to detect the chemical structure of a surface.17 Time-dependent ATR-FTIR has been used as an effective method to monitor the gas or liquid diffusion process inside polymer films at real time.18−22 In this research, time-dependent ATR-FTIR was used to in situ monitor the molecular diffusion process inside GO membranes for the first time. Four common 3



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organic solvents, c-hexane, ethylene glycol (EG), dimethyl sulfoxide (DMSO), and N, N-dimethylformamide (DMF) were chosen as typical diffusates. The diffusion coefficients from time-dependent ATR-FTIR are obtained, and they are in consistent with those calculated from traditional gravimetric method. Moreover, the interaction between these molecules and GO sheets was also characterized at the same time. When diffusing into GO membranes, the characteristic absorption peaks of solvent molecules shifted in varying degrees compared with their bulk state. The time-dependent ATR-FTIR spectroscopy would be an efficient and powerful technique to explore the molecular diffusion mechanism in GO membranes.

EXPERIMENTAL METHODS Graphene oxide (GO) was prepared from natural graphite powder by a modified Hummers method.2,23 The details are described in Supporting Information. Then GO membranes were fabricated by vacuum-filtrating GO suspensions through nylon microfiltration membranes. After dried in air, free-standing GO membranes were peeled off from the underlying microfiltration membranes. The experimental configuration for the diffusion tests is illustrated in Figure 1. Specifically, a solvent container was made by capping one end of a hollow tube with the free-standing GO membrane and sealing with silicone sealant. During the tests, GO membrane was attached closely onto the ATR crystal. The spectrum of the dry GO membrane was collected as background. Then the solvents were injected into the solvent container, and we immediately started to collect the IR spectra at given interval time. All the 4


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time-dependent infrared spectra were recorded at 24 °C by FTIR spectrometer (PerkinElmer, MA, USA) attached the general ATR sampling accessory (PerkinElmer, MA, USA). The diamond/ZnSe trapezoidal IRE ATR crystal has refractive index of 2.417. The incidence angle is 45° giving three reflections in contact with the sample. The series of spectra were measured at 4 cm−1 resolution with eight scans. The wavenumber range was from 4000 to 650 cm−1. Atomic force microscopy (AFM) image was obtained using a SPM9600 (Shimadzu, Japan). Samples for AFM test were made by depositing a diluted GO solution onto a freshly cleaved mica. Scanning electron micrograph (SEM) images were taken using a Sirion 200 scanning electron microscope (JEOL, Japan). X-ray diffraction (XRD) was performed on a D8 Advance X-ray diffractometer with Cu Kα radiation (λ = 0.15418 nm, Bruker, Germany). X-ray photoelectron spectroscopy (XPS) spectra were taken using an ESCALAB 250XI photoelectron spectrometer (ThermoFisher Scientific, USA).

Figure 1. Schematic diagram of (a) the experimental configuration; (b) the diffusion of solvent molecules through GO membranes.

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RESULTS AND DISCUSSION As shown by the AFM image, the as-prepared GO sheets are single-layered with a thickness of about 1 nm, and a lateral dimension of several micrometers (Figure 2a). As we can see from the SEM images (Figure S2, Supporting Information, and Figure 2b), GO membrane has a relative smooth surface without any cracks and a thickness of about 10 µm, exhibiting a layered structure as previously reported.24 The layered structure of GO membrane was confirmed by XRD. The XRD diffraction peak of GO membrane is centered at 2θ=10.95°, so the layer-to-layer distance between GO sheets is about 0.81 nm (Figure 3a). As shown in XPS spectra (Figure S3, Supporting Information, and Figure 3b), GO membrane has a C/O ratio of 2.64, and the C1s XPS spectrum of GO membrane can be separated into four peaks, assigned to four types of carbon bonds of GO, C−C/C=C (284.6 eV), C−OH/C−O−C (286.6 eV), C=O (287.0 eV) and C(O)−OH (289.2 eV), respectively.25

This indicates the existence of

oxygen-containing groups (hydroxyl, epoxy, carbonyl and carboxyl) in GO membrane.

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Figure 2. (a) AFM image of GO sheets; (b) Cross-section SEM image of GO membrane.

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Figure 3. XRD pattern (a) and C1s XPS spectrum (b) of GO membrane.

The diffusion processes of several organic solvents in GO membrane were monitored by ATR-FTIR. As shown in Figure 4a, there was no absorption peak related to DMF in the ATR-FTIR spectra at the beginning of the diffusion, because the thickness of GO membrane (~10 µm) is much larger than the penetration depth of the evanescent wave (~1 µm at 1000 cm−1). When DMF molecules diffused through the GO membrane into the evanescent field, the characteristic absorption bands of DMF appeared in the ATR-FTIR spectra, increased with the diffusion time, and finally reached an equilibrium. The same trend was observed for DMSO and EG (Figure 4b and c).

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Figure 4. Typical time-dependent ATR-FTIR spectra during the diffusion process of each solvent. (a) DMF, (b) DMSO, (c) EG. More specifically, the ν(C=O) absorption peak of DMF appeared at 1630 cm−1 after only 15 minutes. With the increase of diffusion time, this peak exhibited a blue-shift and finally stabilized at 1649 cm−1 (Figure 4a). However, compared with the ν(C=O) absorption peak of bulk DMF (1662 cm−1), DMF molecules diffusing into GO membrane at the equilibrium still exhibited a red shift of 13 cm−1 (Figure 4a). 9



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This can be explained as follows. At the early stage of the diffusion, all DMF molecules diffusing into GO membranes were able to form strong hydrogen bond with the oxygen-containing functional groups on GO sheets.26 So the ν(C=O) absorption peak red-shifted to 1630 cm−1 at the beginning. However, with more and more DMF molecules diffusing into GO membrane, the hydrogen-bond forming sites on GO sheets were all occupied. Therefore, some DMF molecules would not be able to form hydrogen bond with GO sheets and the ν(C=O) absorption peak would appear at 1662 cm−1, as the case in their bulk state. These two peaks at 1630 cm−1 and 1662 cm−1 would overlap into a new peak between them. With the diffusion proceeding, the amount of DMF molecules which do not form hydrogen bond with GO sheets would increase. So compared with the peak at 1630 cm−1, the intensity of the peak at 1662 cm−1 would increase. As a result, their overlapping peak would blue-shift to the side of 1662 cm−1. In addition, the C(O)−N stretching bond (1256 cm−1 in bulk DMF) red-shifted to 1254 cm−1 and the C(H3)−N stretching bond (1089 cm−1 in bulk DMF) blue-shifted to 1090 cm−1. These phenomena cannot be explained by the formation of hydrogen bonding. Because the nitrogen atom in DMF is surrounded by two methyl groups and its ability to form hydrogen bond is greatly reduced. A plausible explanation may be that these vibrations in DMF molecule are restricted when confined in the 2D nanochannels of GO membrane. Bulk DMSO is highly associated and contains both monomers and cyclic dimers.27 The peak at 1012 cm−1 is the CH3 wagging band of monomer,28 the peak at 1026 cm−1 is the CH3 wagging band of dimer,28 and the peak at 1042 cm−1 is the S=O 10


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stretching band of dimer29. Bulk DMSO shows two strong peaks at 1042 and 1026 cm−1, implying that DMSO molecules exist mainly in the dimer form. As shown in Figure 4b, at the moment when DMSO molecules just diffused into GO membrane, there appeared a strong peak at 1012 cm−1, which belongs to the CH3 wagging band of DMSO monomer. With the increase of diffusion time, a weak shoulder peak attributing to the S=O stretching band of dimer showed up at 1042 cm−1. These observations suggest that at the beginning of the diffusion process, DMSO molecules diffused into GO membrane in the form of monomer. With more and more DMSO molecules diffusing into GO membrane, a fraction of DMSO monomer transformed to dimer. However, even at equilibrium, the amount of monomers was much more than that of dimers. So DMSO molecules mainly exist in the monomer form when diffusing into GO membrane. In other words, the dimers in bulk DMSO disassociated when they diffused into GO membrane. In addition, the ω(CH3) band of DMSO showed an obvious shift to the higher energy, which again may be attributed to the confine effect of 2D nanochannels in GO membrane. Bulk EG has a strong peak of the O−H stretching mode at 3306 cm−1 and another strong peak of the C−O stretching mode at 1033 cm−1. These two peaks both exhibited red-shift during the diffusion process compared with the bulk EG (Figure 4c). These results suggest that EG could form strong hydrogen bond with GO sheets as both proton donor and proton acceptor. No absorption band of c-hexane was detected within 150 minutes (Figure S4, Supporting Information).

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Table 1. IR band identification Wave number (cm−1)

assignment

1650 1256 1089 1030 1042 1026 1012 2923

C=O stretching band of DMF C(O)−N stretching bond of DMF C(H3)−N stretching bond of DMF C–O stretching band of EG S=O stretching band of DMSO dimer CH3 wagging band of DMSO dimer CH3 wagging band of DMSO monomer CH2 stretching band of c-hexane

references 26 26

29 28 28

For the quantitative description of the diffusion behaviours of the solvent molecules in GO membrane, the diffusion coefficient (D) of each solvent was calculated from the time-dependent ATR-FTIR spectra using Fickian diffusion equation: 30   2 2  exp  −D( 2n + 1) π t  ( 2n + 1)π exp( −2γ L ) + ( −1)n( 2γ )       2 ∞  2L 4L 8γ    At = 1 −   ∑ 2 [ 1 − exp( − 2 L ) ] π γ  n =0   ( 2n + 1)π   Ae 2 ( 2n + 1)  4γ +      2 L      

(1)

where At and Ae are the area of the chosen absorption band of the solvent at time t and equilibrium. L is the thickness of the GO membrane. γ is the reciprocal of dP (the penetration depth of the evanescent wave) (Equation (2)). D is the diffusion coefficient.

λ

dP =

(2)

n  2n2π si n2 θ −  1   n2 

2

λ is the wavelength of the infrared beam, θ is the incidence angle of radiation, n1 is the refractive index of the GO membrane, and n2 is the refractive index of the ATR crystal. When At/Ae c-hexane. To explain this phenomenon, Hansen solubility parameters and Taft-Kamlet’s scales are introduced, and these solvent empirical parameters are consistent with the information from ATR-FTIR spectra. For nonpolar solvent like c-hexane, the diffusion coefficient is extremely low because it is repulsed by GO sheets. On the contrary, polar solvent (DMF, DMSO and EG) molecules could penetrate GO membrane because the significant interaction between them and GO sheets can pull them into the nanochannels in GO membranes. However, as the solvent-GO interaction become stronger, the retention time of the solvent molecules would increase, so the diffusion coefficients decrease. Moreover, time-dependent ATR-FTIR method is versatile and can be extended to investigate the diffusion process of various molecules in GO membranes, thus predicting the separation performance of GO membranes.

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ASSOCIATED CONTENT

Supporting Information

The Supporting Information is available free of charge on the ACS Publications website at DOI: xxxxxx.

Details of preparing GO membranes and conventional gravimetric method, supplementary Figure S1−S10 and Table S1−S2.

AUTHOR INFORMATION Corresponding Author E-mail: [email protected] Tel: (+86)10 6278 1689 Notes The authors declare no competing financial interests.

ACKNOWLEDGMENTS

This research was supported by the National Natural Science Foundation of China (No. 31370556).

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REFERENCES

(1) Huang, L.; Zhang, M.; Li, C.; Shi, G. Q., Graphene-Based Membranes for Molecular Separation. J. Phys. Chem. Lett. 2015, 6, 2806−2815.

(2) Hummers, W. S.; Offeman, R. E., Preparation of Graphitic Oxide. J. Am. Chem.

Soc. 1958, 80, 1339−1339.

(3) Xu, Y. X.; Bai, H.; Lu, G. W.; Li, C.; Shi, G. Q., Flexible Graphene Films via the Filtration of Water-Soluble Noncovalent Functionalized Graphene Sheets. J. Am.

Chem. Soc. 2008, 130, 5856−5857.

(4) Cheng, H. H.; Hu, Y.; Zhao, F.; Dong, Z. L.; Wang, Y. H.; Chen, N.; Zhang, Z. P.; Qu, L. T., Moisture-Activated Torsional Graphene-Fiber Motor. Adv. Mater. 2014,

26, 2909−2913.

(5) Hu, C. G.; Zhao, Y.; Cheng, H. H.; Hu, Y.; Shi, G. Q.; Dai, L.; Qu, L. T., Ternary Pd-2/PtFe Networks Supported by 3D Graphene for Efficient and Durable Electrooxidation of Formic Acid. Chem. Commun. 2012, 48, 11865−11867.

(6) Kim, H. W.; Yoon, H. W.; Yoon, S. M.; Yoo, B. M.; Ahn, B. K.; Cho, Y. H.; Shin, H. J.; Yang, H.; Paik, U.; Kwon, S. et al, Selective Gas Transport Through Few-Layered Graphene and Graphene Oxide Membranes. Science 2013, 342, 91−95.

(7) Li, H.; Song, Z. N.; Zhang, X. J.; Huang, Y.; Li, S. G.; Mao, Y. T.; Ploehn, H. J.; Bao, Y.; Yu, M., Ultrathin, Molecular-Sieving Graphene Oxide Membranes for Selective Hydrogen Separation. Science 2013, 342, 95−98. 19



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

(8) Nair, R. R.; Wu, H. A.; Jayaram, P. N.; Grigorieva, I. V.; Geim, A. K., Unimpeded Permeation of Water Through Helium-Leak-Tight Graphene-Based Membranes. Science 2012, 335, 442−444.

(9) Han, Y.; Xu, Z.; Gao, C., Ultrathin Graphene Nanofiltration Membrane for Water Purification. Adv. Funct. Mater. 2013, 23, 3693−3700.

(10) Sun, P. Z.; Liu, H.; Wang, K. L.; Zhong, M. L.; Wu, D. H.; Zhu, H. W., Ultrafast Liquid Water Transport Through Graphene-Based Nanochannels Measured by Isotope Labelling. Chem. Commun. 2015, 51, 3251−3254.

(11) Liu, R.; Arabale, G.; Kim, J.; Sun, K.; Lee, Y.; Ryu, C.; Lee, C., Graphene Oxide Membrane for Liquid Phase Organic Molecular Separation. Carbon 2014, 77, 933−938.

(12) Tang, Y. P.; Paul, D. R.; Chung, T. S., Free-Standing Graphene Oxide Thin Films Assembled by a Pressurized Ultrafiltration Method for Dehydration of Ethanol.

J. Membr. Sci. 2014, 458, 199−208.

(13) Li, G. H.; Shi, L.; Zeng, G. F.; Li, M.; Zhang, Y. F.; Sun, Y. H., Sharp Molecular-Sieving of Alcohol-Water Mixtures over Phenyldiboronic Acid Pillared Graphene Oxide Framework (GOF) Hybrid Membrane. Chem. Commun. 2015, 51, 7345−7348.

20


Page 20 of 26

Page 21 of 26

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(14) Huang, H. B.; Mao, Y. Y.; Ying, Y. L.; Liu, Y.; Sun, L. W.; Peng, X. S., Salt Concentration, pH and Pressure Controlled Separation of Small Molecules Through Lamellar Graphene Oxide Membranes. Chem. Commun. 2013, 49, 5963−5965.

(15) Qiu, L.; Zhang, X. H.; Yang, W. R.; Wang, Y. F.; Simon, G. P.; Li, D., Controllable Corrugation of Chemically Converted Graphene Sheets in Water and Potential Application for Nanofiltration. Chem. Commun. 2011, 47, 5810−5812.

(16) Wang, W. T.; Eftekhari, E.; Zhu, G. S.; Zhang, X. W.; Yan, Z. F.; Li, Q., Graphene Oxide Membranes with Tunable Permeability Due to Embedded Carbon Dots. Chem. Commun. 2014, 50, 13089−13092.

(17) Boknam, C.; Yu Hyun, K.; Young Mee, J.; Do-Hung, H.; Seung Bin, K.; Seung Woo, L., Spectroscopic and Thermal Degradation Studies of Polystyrene Grafting

onto

Poly(tetrafluoroethylene-co-hexafluoropropylene)

Films

via

Electron-Beam Irradiation. Vib. Spectrosc. 2009, 51, 72−75.

(18) Breen, A. F.; Breen, C.; Clegg, F.; Doppers, L. M.; Khairuddin; Labet, M.; Sammon, C.; Yarwood, J., FTIR-ATR Studies of the Sorption and Diffusion of Acetone:Water Mixtures in Poly(vinyl alcohol)-Clay Nanocomposites. Polymer 2012,

53, 4420−4428.

(19) Doppers, L. M.; Sammon, C.; Breen, C.; Yarwood, J., FTIR-ATR Studies of the Sorption and Diffusion of Acetone/Water Mixtures in Poly(vinyl alcohol).

Polymer 2006, 47, 2714−2722.

21



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

(20) Hajatdoost, S.; Sammon, C.; Yarwood, J., FTIR-ATR Studies of Diffusion and Perturbation of Water in Polyelectrolyte Thin Films. Part 4. Diffusion, Perturbation and Swelling Processes for Ionic Solutions in SPEES/PES Membranes. Polymer 2002, 43, 1821−1827.

(21) Yang, H. X.; Sun, M.; Zhou, P., Investigation of Water Diffusion in Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) by Generalized Two-Dimensional Correlation ATR-FTIR Spectroscopy. Polymer 2009, 50, 1533−1540.

(22) Dlamini, D. S.; Levchenko, S.; Bass, M.; Mamba, B. B.; Hoek, E. M. V.; Thwala, J. M.; Freger, V., Solute Hindrance in Non-porous Membranes: An ATR-FTIR Study. Desalination 2015, 368, 60−68.

(23) Huang, L.; Li, Y. R.; Zhou, Q. Q.; Yuan, W. J.; Shi, G. Q., Graphene Oxide Membranes with Tunable Semipermeability in Organic Solvents. Adv. Mater. 2015,

27, 3797−3802.

(24) Dikin, D. A.; Stankovich, S.; Zimney, E. J.; Piner, R. D.; Dommett, G. H. B.; Evmenenko, G.; Nguyen, S. T.; Ruoff, R. S., Preparation and Characterization of Graphene Oxide Paper. Nature 2007, 448, 457−460.

(25) Yang, D.; Velamakanni, A.; Bozoklu, G.; Park, S.; Stoller, M.; Piner, R. D.; Stankovich, S.; Jung, I.; Field, D. A.; Ventrice Jr, C. A. et al, Chemical analysis of graphene oxide films after heat and chemical treatments by X-ray photoelectron and Micro-Raman spectroscopy. Carbon 2009, 47, 145−152.

22


Page 22 of 26

Page 23 of 26

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(26) Zhang, C.; Ren, Z.; Liu, L.; Yin, Z., Modelling Hydrogen Bonds in NN-dimethylformamide. Mol. Simul. 2013, 39, 875−881.

(27) Vaisman, II; Berkowitz, M. L., Local Structural Order and Molecular Associations in Water DMSO Mixtures. Molecular Dynamics Study. J. Am. Chem.

Soc. 1992, 114, 7889−7896.

(28) Fawcett, W. R.; Kloss, A. A., Attenuated Total Reflection Fourier-transform IR Spectroscopic Study of Dimethyl Aulfoxide Aelf-association in Acetonitrile Solutions. J. Chem. Soc., Faraday Trans. 1996, 92, 3333−3337.

(29) Forel, M. T.; Tranquille, M., Spectres de vibration du diméthylsulfoxyde et dn diméthylsulfoxyde-d6. Spectrochim. Acta. A 1970, 26, 1023−1034.

(30) Fieldson, G. T.; Barbari, T. A., The Use of FTIR-ATR Spectroscopy to Characterize Penetrant Diffusion in Polymers. Polymer 1993, 34, 1146−1153.

(31) Lively, R. P.; Dose, M. E.; Thompson, J. A.; McCool, B. A.; Chance, R. R.; Koros, W. J., Ethanol and Water Adsorption in Methanol-Derived ZIF-71. Chem.

Commun. 2011, 47, 8667−8669.

(32) Hu, C. L.; Guo, R. L.; Li, B.; Ma, X. C.; Wu, H.; Jiang, Z. Y., Development of Novel Mordenite-Filled Chitosan-Poly(acrylic acid) Polyelectrolyte Complex Membranes for Pervaporation Dehydration of Ethylene Glycol Aqueous Solution. J.

Membr. Sci. 2007, 293, 142−150.

23



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 24 of 26

(33) Hansen, C. M., Hansen Solubility Parameters: A User’s Handbook, CRC Press: Hoboken, 2nd edn, 2007.

(34) Taft, R. W.; Kamlet, M. J., Solvatochromic Comparison Method .2. Alpha-Scale of Solvent Hydrogen-Bond Donor (Hbd) Acidities. J. Am. Chem. Soc. 1976, 98, 2886−2894.

(35) Taft, R. W.; Abboud, J. L. M.; Kamlet, M. J., Solvatochromic Comparison Method .20. Linear Solvation Energy Relationships .12. the D-Delta-Term in the Solvatochromic Equations. J. Am. Chem. Soc. 1981, 103, 1080−1086.

(36) Taft, R. W.; Abraham, M. H.; Doherty, R. M.; Kamlet, M. J., Linear Solvation Energy Relationships .29. Solution Properties of Some Tetraalkylammonium Halide Ion-Pairs and Dissociated Ions. J. Am. Chem. Soc. 1985, 107, 3105−3110.

(37) Marcus, Y., The Effectiveness of Solvents as Hydrogen-Bond Donors. J.

Solution Chem. 1991, 20, 929−944.

(38) Ruoff, R. S.; Tse, D. S.; Malhotra, R.; Lorents, D. C., Solubility of Fullerene (C60) in a Variety of Solvents. J. Phys. Chem. 1993, 97, 3379−3383.

(39) Bergin, S. D.; Sun, Z. Y.; Rickard, D.; Streich, P. V.; Hamilton, J. P.; Coleman, J.

N.,

Multicomponent

Solubility

Parameters

for

Nanotube-Solvent Mixtures. ACS Nano 2009, 3, 2340−2350.

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Single-Walled

Carbon

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(40) Park, S.; An, J. H.; Jung, I. W.; Piner, R. D.; An, S. J.; Li, X. S.; Velamakanni, A.; Ruoff, R. S., Colloidal Suspensions of Highly Reduced Graphene Oxide in a Wide Variety of Organic Solvents. Nano Lett. 2009, 9, 1593−1597.

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In Situ Monitoring the Molecular Diffusion Process ... - ACS Publications

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