Supporting Information

� Wiley-VCH 2014

69451 Weinheim, Germany

Ending Aging in Super Glassy Polymer Membranes**Cher Hon Lau, Phuc Tien Nguyen, Matthew R. Hill,* Aaron W. Thornton, Kristina Konstas,Cara M. Doherty, Roger J. Mulder, Laure Bourgeois, Amelia C. Y. Liu, David J. Sprouster,James P. Sullivan, Timothy J. Bastow, Anita J. Hill, Douglas L. Gin, and Richard D. Noble*

ange_201402234_sm_miscellaneous_information.pdf

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Forever Young: Ending Aging in Super-Glassy Polymer Membranes

Authors: Cher Hon Lau,1 Phuc Tien Nguyen,2 Matthew R. Hill,1* Aaron W. Thornton,1 Kristina Konstas,1 Cara M. Doherty,1 Roger J. Mulder,1 Laure Bourgeois,3 Amelia Liu,4

David J. Sprouster,5 James P. Sullivan,5 Timothy J. Bastow,1 Anita J. Hill, 1 Douglas L. Gin,2 and Richard D. Noble2*

Affiliations: 1 CSIRO Materials Science and Engineering and Process Science and Engineering, Private Bag 33, Clayton South MDC, Victoria 3169 Australia. 2 Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO 80309 USA. 3 Monash Centre for Electron Microscopy, Department of Materials Engineering, Monash University, Clayton Victoria 3800 Australia 4 Monash Centre for Electron Microscopy, School of Physics, Monash University, Clayton Victoria 3800 Australia 5 ARC Centre for Antimatter-Matter Studies, Research School of Physics, Australian National University, Canberra, ACT 0200, Australia

*Correspondence to: matthew.hill@csiro.au, nobler@colorado.edu

Experimental details

1. Materials a. Synthesis of PAF-1 b. Synthesis of PMP c. Synthesis of PIM-1 d. Fabrication of PTMSP/PAF-1 membrane e. Fabrication of PMP/PAF-1 membrane f. Fabrication of PIM-1/PAF-1 membrane

2. BET measurements 3. Single gas permeability measurements 4. Scanning Electron Microscopy (SEM) and Scanning Transmission Electron

Microscopy (STEM) 5. Slow Beam and Bulk Positron Annihilation Lifetime Spectroscopy 6. CO2 sorption measurements 7. 13C solid state Nuclear Magnetic Resonance Spectroscopy 8. Mathematical modelling 9. References

2

1. Materials Polytrimethylsilylpropyne (PTMSP) was purchased from Gelest Inc. (Morrisville PA, USA) and used without purification. 4-methyl-2-pentyne was purchased from GFS Chemicals, Inc (Powell OH, USA). 5,5’6,6’-tetrahydroxy-3,3,3’,3’-tetramethylspirobisindane was purchased from Alfa Aesar. 1,4-dicyanotetrafluorobenzene, potassium carbonate (K2CO3), niobium pentachloride (NbCl5), triphenyl bismuth (Ph3Bi), calcium hydride, 1,5-cyclooctadiene, bis(1,5-cyclooctadiene) nickel, 2,2’-bipyridyl, and tetrakis(4-bromophenyl) methane were purchased from Sigma Aldrich. Dimethylacetamide (DMAc), toluene, dimethylformamide (DMF), chloroform, hydrochloric acid (HCl), carbon tetrachloride (CCl4) were also used.

a. Synthesis of PAF-1 PAF-1 was synthesized according to Zhu and co-workers[1] to yield an off-white powder with a BET surface area of 3760 m2/g). Briefly, 1,5-cyclooctadiene (dried over CaH2) was added into a solution of bis(1,5-cyclooctadiene) nickel and 2,2’-bipyridyl in dehydrated DMF. The mixture was heated for 1 hour at 80 °C to form a purple solution. Tetrakis(4-bromophenyl)methane was added and the mixture was stirred overnight at 80 °C. The mixture was allowed to cool to room temperature and concentrated HCl was added. The solids were collected and washed with chloroform, THF, and deionized water. The particle size was typically in the range of 100-200 nm.

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b. Synthesis of PMP

PMP was synthesized according to Morisato and Pinnau [2] to yield a white thread-like polymer. Niobium pentachloride (NbCl5) was vacuum sublimated at 180 °C and triphenyl bismuth (Ph3Bi) was recrystallised from ethanol and were used as catalysts, while dehydrated toluene was used. 4-methyl-2-pentyne was dried over calcium hydride under argon for 24 hours prior use. 2 g of dried 4-methyl-2-pentyne was mixed with 2.8 ml of toluene and stirred for 20 minutes. A solution of 0.271 g NbCl5, 0.428 g Ph3Bi, and 21.6 ml toluene was stirred at 90 °C for 20 mins under argon flow. The monomer solution was added dropwise to the catalyst solution. The viscosity of the solution increased rapidly and a brown, opaque gel was formed within 5 minutes. The gel was transferred into methanol and stirred for 2 – 3 hours until the brown gel turns into a white solid. The white solid was dissolved in carbon tetrachloride at 80 °C. This polymer/CCl4 solution was poured slowly into methanol at room temperature to form white thread-like polymer strands and stirred for 2 -3 hours. The polymer was dissolved in CCl4 solution and reprecipitated from methanol again, till the methanol solution was clear. The density of the polymer was determined using a helium pcynometer. The density of PMP synthesized in this work is 0.78 g/cm3. The elemental analysis of PMP was performed using an ATR-FTIR, and the IR-spectrum (Figure S1) is in good agreement with that reported by Masuda et al.[3] and Morisato and Pinnau.[4]

Figure S1 ATR-FTIR spectrum of PMP synthesized in this work.

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c. Synthesis of PIM-1 PIM-1 was synthesized using the high temperature approach formulated by Du et al.[5] 5,5’6,6’-tetrahydroxy-3,3,3’,3’-tetramethylspirobisindane (TTSBI) was recrystallised from methanol at 60 °C at least three times before use. 1,4-dicyanotetrafluorobenzene (TFB) was vacuum sublimated at least three times at 150 °C prior use. K2CO3 was dried at 100 °C under vacuum before use. DMAc was dried using 4 Å molecular sieves, while dehydrated toluene was used. 1 g TTSBI, 1.702 g TFB, and 1.797 g of K2CO3 were placed in a 100 mL round bottom flask and dried under vacuum at 100 °C and flushed with argon for at least 3 times. 20 mL of dehydrated DMAc and 10 mL of dehydrated toluene was discharged into the round bottom flask containing the pre-dried monomers. The mixture was stirred at 160 °C for 1 hour, of which, condensation could be observed in the Dean-Stark trap during the first 20 minutes of stirring. The yellow solution was allowed to stir under argon flow for the next 40 minutes. This yellow viscous solution was then poured into a methanol solution at room temperature to form fluorescent yellow polymer threads. This solution was filtered and the precipitate was dried. The yellow polymer threads were re-dissolved in chloroform and re-precipitated in methanol. The final yellow product was refluxed in deionized water for 24 hours to remove remainder K2CO3 salt. The density of the polymer was determined using a helium pcynometer. The density of PIM-1 synthesized in this work is 1.05 g/cm3. The elemental analysis of PMP was performed using an ATR-FTIR, and the IR-spectrum (Figure S2) is in good agreement with that reported by Du et al. [5]

Figure S2 ATR-FTIR spectrum of PIM-1 synthesized in this work.

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d. Fabrication of PTMSP/PAF-1 membrane 10 wt. % of PAF-1 was mixed with PTMSP. 9.67 g of tetrahydrofuran was added to the mixture. The solution was stirred for 24 h at ambient conditions. ̴ 100 µm films were formed via solution casting at ambient conditions. The membrane films were dried in a vacuum oven at 40 °C for 24 h prior single gas permeability measurements. The densities of these films were measured using a helium pycnometer.

e. Fabrication of PMP/PAF-1 membrane 10 wt. % of PAF-1 was mixed with PMP. 9.67 g of cyclohexane was added to the mixture. The solution was stirred for 48 h at ambient conditions. ̴ 100 µm films were formed via solution casting at ambient conditions. The membrane films were dried in a vacuum oven at 40 °C for 24 h prior single gas permeability measurements. The densities of these films were measured using a helium pycnometer.

f. Fabrication of PIM-1/PAF-1 membrane 10 wt. % of PAF-1 was mixed with PIM-1. 9.67 g of chloroform was added to the mixture. The solution was stirred for 24 h at ambient conditions. ̴ 100 µm films were formed via solution casting at ambient conditions. The membrane films were dried in a vacuum oven at 40 °C for 24 h prior single gas permeability measurements. The densities of these films were measured using a helium pycnometer.

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2. BET measurements Gas adsorption isotherms between the range of 0 – 700 mmHg were measured by a volumetric approach using a Micrometrics ASAP 2420 instrument. All the samples were transferred to pre-dried analysis tubes, sealed with Transeal stoppers, evacuated and activated at 120 °C under a 10-6 dynamic vacuum for 24 hours. Ultra-high purity N2 and CO2 gases were used for these experiments. N2 adsorption measurements were conducted at 77 K, while CO2 adsorption measurements were done at 273 K. N2 adsorption measurements at 77 K in Figure S3 were used to determine the BET surface areas of PAF-1 nanoparticles. The BET surface area of PAF-1 is 3760 m2/g.

Figure S3 N2 adsorption isotherm of PAF-1

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3. Single gas permeability measurements The pure N2, and CO2 permeabilities were determined using a constant volume and variable pressure method.[6] Gas permeabilities at 2 atm were determined from the rate of downstream pressure build-up rate (dp/dt) obtained when permeation reached a steady state according to the following equation:

P refers to the permeability of a membrane to a gas and its unit is in Barrer (1 Barrer = 1 × 10-10 cm3 (STP)-cm/cm2 sec cmHg),[7] D is the average effective diffusivity (cm2/s), S is the apparent sorption coefficient/solubility (cm3 (STP)/cm3 polymer cmHg), V is the volume of the downstream chamber (cm3), L is the film thickness (cm). A refers to the effective area of the membrane (cm2), T is the experimental temperature (K) and the pressure of the feed gas in the upstream chamber is given by p2 (psia).

Figure S4. The N2 permeabilities of (i) PTMSP – based, (ii) PMP – based, and (iii) PIM-1 – based nanocomposites. Lines are drawn to guide the eye. The deviation of these permeability measurements is within ±10 %.

P= D × S= 273×1010

760VL

AT[p2 × 7614.7

](dpdt

)

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Scanning Electron Microscopy (SEM) and Scanning Transmission Electron Microscopy (STEM)

All membrane films were cryo-fractured, to achieve a clean break, and then mounted on cross-section SEM sample stubs. These sample stubs were then coated with iridium for elemental analysis through energy dispersive spectroscopy (EDS) during imaging. Powdered samples (PAF-1, and polymer-infiltrated PAF-1) were also characterised using SEM and EDS. To prepare polymer-infiltrated PAF-1 powder, 10 wt. % of PAF-1 nanoparticles were dispersed in a polymer solution (polymer concentration is equivalent to those used in membrane fabrication). The PAF-1/polymer solution was stirred for 24 hours, filtered, and the wet powders were rigorously washed with toluene to flush out any polymer coated on the surface of the PAF-1 nanoparticles. The PAF-polymer powder was then dried in a vacuum oven at 80 °C for 24 hours.

Two methods were used for TEM sample preparation: the PTMSP/PAF-1 membrane shown in Fig. 1C was embedded in Embed 812 epoxy resin using standard method for hard resin. The embedded membrane was sectioned by using Leica EM UC 7 microtome at room temperature with a DiATOME Ultra 45° diamond knife. Sections with 50nm thickness were collected on 400 mesh thin bar copper grids and sections with 30nm, 20nm thickness on holey carbon film coated copper grids. The material shown in Fig. 1D was prepared by absorbing PTMSP into the PAF-1 pores by slow evaporation of a chloroform solution. The dried powder was washed with chloroform, and then dispersed in its powder form with high-purity ethanol, depositing a drop of the suspension onto a copper grid coated with holey-carbon film.

The microscopy was performed on a JEOL JEM 2100F FEG TEM/STEM operated at 200 kV. The HRTEM images were collected using a Gatan Ultrascan 1000 (2kx2k) CCD Camera. Boundaries in refractive index due to nanoparticle/matrix interfaces were highlighted by employing large values of defocus. Bright Field (BF) and High-Angle Annular Dark Field (HAADF) STEM images were obtained using a 2 nm STEM probe. EDS spectra were obtained using a JEOL 50 mm2 Si(Li) detector. X-ray maps (512x512) were obtained using 50-100 sweeps of the same area, drift correction and probe dwell times of 0.2 msec, resulting in total acquisition times of 30-60 minutes.

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Figure S5 SEM images of fresh chloroform-casted PTMSP membrane film at (a) 500 x, (b)

5,000 x magnifications and PTMSP-PAF films at (c) 500 x, (d) 5,000 x, (e) 20,000 x, (f) 50,000 x

magnifications.

(a)

(b)

(f)

(e)

(d)

(c)

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Figure S6 SEM images of fresh cyclohexane-casted PMP membrane film at (a) 500 x, (b)

5,000 x, (c) 20,000 x, (d) 50,000 x magnifications and PMP-PAF films at (e) 500 x, (f) 5,000 x,

(g) 20,000 x, (h) 50,000 x magnifications

(a)

(b)

(c)

(d) (h)

(g)

(f)

(e)

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Figure S7 SEM images of fresh cyclohexane-casted PIM-1 membrane film at (a) 500 x, (b)

5,000 x, (c) 20,000 x, (d) 50,000 x magnifications and PIM-1/PAF-1 films at (e) 500 x, (f) 5,000

x, (g) 20,000 x, (h) 50,000 x magnifications

(h)

(e)

(g)

(f)

(d)

(c)

(b)

(a)

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Figure S8 SEM images and EDX analysis of fresh PIM-1/PAF-1 powders.

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Figure S9 STEM images and EDX analysis of PTMSP/PAF-1 nanocomposite films.

PAF-1 PTMSP

Vacuum

Vacuum C Si

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4. Positron Annihilation Lifetime Spectroscopy The PALS experiment measures the lifetimes of positrons, the antiparticles of electrons, by detecting start quanta of 1.28 MeV associated with their birth, and stop quanta of 0.51 MeV associated with their death. Inside the sample, positrons may form ortho-positronium (o-Ps), which in microporous and mesoporous materials is used to probe porosity, surface area and pore size distributions (PSDs).

Beam-line PALS experiments used to characterize aging in the surface layers of sample films were conducted at The Australian National University using a Surko buffer gas trap beamline.[8] The source chamber and cold head assembly was manufactured by First Point Scientific Inc. The beamline uses a 22Na source with a half-life of 2.6 years, which currently has an activity of ≈25 mCi. The source is mounted on the cold head, which is held at 6.8 K, inside a vacuum chamber pumped by a 210 L s−1 turbomolecular pump. This chamber is surrounded by Elkonite (a tungsten copper alloy) which provides primary shielding from the high energy (1.27 MeV) gamma rays produced during the β+ decay of the source. Additional shielding is provided by lead shot which fills a 400 mm diameter cylindrical tank housing the chamber. The resolution function of the beam is 800 ps FWHM. 10 mm x 10 mm sample films were mounted on a stainless steel stub and measured with beam energy of 5 keV. With this energy, positrons penetrated up to 500 nm of the film i.e. aging in the surface was tracked using beam PALS. Spectra of at least one and a half million integrated counts were collected with each spectrum taking about 2 hours to collect. The lifetime components within each sample were determined by fitting the experimentally measured spectra (A(t)) to:

���� = ���� × +� R�t� × exp �− �� �

�

��+ �

where t is time, R(t) is the instrument resolution function, τi is the mean lifetime of the ith component, Ii is the relative intensity of the ith component and B is the background. The I0 component incorporates the instrument function itself into the fit, which accounts for all the short (<0.2 ns) lifetime components in the annihilation Each spectrum was fitted using a nonlinear fitting routine with an experimentally determined R(t) spectrum using an kapton sample measured at 5 keV to account for the temporal shape of the positron pulse and gas tail intrinsic to our gas-trap PALS beamline. The spectra were best fitted with five components For the long lifetimes obtained, the Tao-Eldrup model[9] traditionally used for calculating mean pore sizes from mean o-Ps lifetimes is not valid; therefore, the mean free path (nm) of the pores was calculated using the Rectangular Tao Eldrup (RTE) model.[10]

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Figure S10 Bulk PALS spectrum of PAF-1 powder.

Figure S11 Solid state 13C NMR spectra of PMP – based nanocomposites. The black solid lines represent the optimal pore size (based on a carbonaceous material) for Knudsen diffusion of CO2 and N2.

[15]

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Table S1 FFV content (bulk PALS) of MOP nanocomposite films studied here

RTE

RTE

RTE

Tau 3 (ns) ± I3 (%) ± Diameter (nm) ± Tau 4 (ns) ± I4 (%) ± Diameter(nm) ± Tau 5 (ns) ± I5(%) ± Diameter(nm) ±

PAF

0.71 0.14 5.21 2.50 0.28

6.92 0.48 2.75 0.33 1.22

58.57 2.19 9.17 1.15 4.79

PTMSP fresh

0.95 0.11 4.36 0.91 0.38 0.08

7.05 0.45 10.74 1.56 1.23 0.07

14.21 0.36 23.27 1.63 1.70 0.04

PTMSP aged 0.97 0.10 4.13 0.94 0.39 0.04

7.33 0.41 10.43 1.18 1.25 0.03

15.03 0.30 22.73 1.38 1.75 0.02

PTMSP-PAF 0 days 1.04 0.08 4.07 0.34 0.41 0.03

6.80 0.23 12.21 0.75 1.21 0.02

14.45 0.25 21.57 0.88 1.72 0.01

15 days 0.96 0.11 4.72 0.64 0.38 0.04

6.68 0.26 12.60 0.63 1.20 0.02

14.73 0.14 20.42 0.66 1.73 0.01

34 days 1.06 0.11 4.46 0.62 0.42 0.04

7.07 0.21 12.55 0.67 1.23 0.02

15.32 0.30 20.46 0.96 1.77 0.02

50 days 1.08 0.09 4.09 0.42 0.42 0.03

7.05 0.31 11.69 0.92 1.23 0.02

15.22 0.28 20.39 1.04 1.76 0.02

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Table S2 FFV content (beam PALS) of MOP nanocomposite films studied here

Name of Sample t3 (ns) r3 (A) I3 (%) FFV % t4 (ns) r4 (A) I4 (%) FFV % t5 (ns) r5 (A) I5 (%) FFV %

As-cast PIM-1 2.91 3.58 12.70 0.58 6.87 5.66 6.85 1.24 0.0000 0

As-cast PIM-1/PAF-1 2.32 3.13 9.62 0.30 6.73 5.61 9.29 1.64 0.0000 0

Aged PIM-1 1.71 2.57 8.23 0.14 5.14 4.91 15.40 1.82 0.0000 0

Aged PIM-1/PAF-1 1.53 2.38 7.17 0.10 6.18 5.38 13.80 2.15 0.0000 0

As-cast PTMSP 0.69 2.97 19.00 0.50 6.62 5.56 14.30 2.46 14.3 8.00 27.70 14.18

As-cast PTMSP/PAF-1 1.07 3.22 4.41 0.15 6.58 5.55 11.50 1.96 14.2 7.98 33.00 16.80

Aged PTMSP 0.42 1.80 14.30 0.08 5.1 4.89 9.29 1.08 14 7.93 27.60 13.77

Aged PTMSP/PAF-1 0.49 1.82 10.20 0.06 6.21 5.39 13.00 2.04 15.2 8.08 29.60 15.59

As-cast PMP 0.96 1.59 5.11 0.02 5.71 5.17 24.70 3.42 14 7.93 14.20 7.09

As-cast PMP/PAF-1 1.07 1.77 3.59 0.02 6.04 5.32 26.10 3.92 13.2 7.72 18.20 8.37

Aged PMP 0.59 0.72 4.60 0.00 4.55 4.61 12.60 1.23 12.5 7.52 15.30 6.52

Aged PMP/PAF-1 0.72 1.11 6.67 0.01 5.83 5.23 25.00 3.57 13.2 7.72 19.10 8.78

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5. CO2 sorption measurements

Pure CO2 sorption measurements in all membrane films were measured via the dual volume pressure decay method using a PCTPro E & E high pressure adsorption workstation (Hy-Energy, Kep Technologies). Specifically, a membrane film was placed in a sample chamber and a vacuum was maintained for 12 hours before CO2 sorption tests were conducted. The CO2 sorption isotherm was maintained at 35 °C up to a maximum pressure of 9 atm over the course of 2 days. New films were used for each CO2 sorption test. The CO2 sorption isotherms of PTMSP and PMP-based membranes are shown in Figures S12 and S13, respectively.

Figure S12 CO2 sorption isotherms of super glassy polymer-based membranes before aging.

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Figure S13 CO2 sorption isotherms of super glassy polymer-based membranes after aging

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6. Solid State Nuclear Magnetic Resonance (NMR) Spectroscopy

Solid State 13C NMR experiments were performed in a manner identical to that described

in a previous publication from the authors.[5] Solid state 13C cross-polarisation/magic-

angle spinning (CP-MAS) NMR spectra were obtained at ambient temperature using a

Bruker MSL-400 MHz or a Bruker Av500 spectrometer with a nominal operating

frequency of 100.61 or 125.8 MHz, respectively for carbon. All 13C chemical shifts were

referenced to external tetramethylsilane (TMS). Each spectrum was the average of 2048

to 33,000 scans with a repetition time of 2 or 5 s and variable decoupling delays from 0.1

to 60 s. Over this range of delay times, relaxation times T1 were determined by fitting to

a single decay exponential function I = Ioexp(t/T1)].

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Figure S14. Solid state 13C NMR relaxivity spectra of PTMSP membranes- 0.1 sec for blue; 0.8 sec for red; 3 sec for purple and 20 sec for green (top), and the assignment of the observed peaks within the PTMSP structure (bottom).

(c)

(b)

(d)

(a)

22

Figure S15. Exponential fit to relaxivity data for NMR peak a in PTMSP/PAF-1.

23

Figure S16. Exponential fit to relaxivity data for NMR peak b in PTMSP/PAF-1.

.

24

Figure S17. Exponential fit to relaxivity data for NMR peak c in PTMSP/PAF-1.

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Figure S18. Exponential fit to relaxivity data for NMR peak d in PTMSP-PAF-1.

Figure S19. Solid state 13C NMR and (B) PALS spectra of PMPChanges in T1 values are measured against those of asArrows denote the increase (↑), decrease (

(a) & (e)

C NMR and (B) PALS spectra of PMP– based nanocomposites. values are measured against those of as-cast super glassy polymer films.

↑), decrease (↓) or no change (−) in molecular mobility.

(a) & (e)

(b) (c) (d)

26

based nanocomposites. cast super glassy polymer films. −) in molecular mobility.

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7. Mathematical modelling

To understand the relationship between pore size distribution and gas separation during aging we adopt a unified transport model combining mechanisms of size sieving activated diffusion, pore size-dependent solubility and Knudsen diffusion. Following the solution-diffusion theory,[12,13] where P= SD, and an approximation of S using Henry’s law,[12,14]

� = ��� � ! "

#��$,

where % is the pore volume, Q represents the gas-membrane interaction energy (approximated as the well depth or condensability), T is the temperature and R is the universal gas constant. The pore size distribution is utilized here to calculate the pore volume by integrating over the gas-accessible volume and the gas-membrane interaction energy by integrating over the potential energy field within a model pore. By assuming a Gaussian distribution, the gas accessible pore volume can be approximated as the integration of the Gaussian function greater than the gas kinetic diameter σ, as follows,

% = & � ! '(�)(*�+,*-..+ /∞

0 1 = √,3, 1455 '1 + �78 " √,,*-.. �1 − 9�$/,

where I is the pore intensity, d is the average pore diameter and derr is the diameter variance. By assuming a cylindrical-shaped pore, the interaction energy between the gas and pore walls can be calculated using the Steel potential outlined in Thornton et al. Finally, diffusivity is approximated using the effective Knudsen diffusivity[15] as follows,

: = *(0;< =>,

where � is the tortuousity (set to unity in this study) and => is the gas velocity calculated as,

=> = "?��3@$.B

,

where m is the gas molecular mass. The effect of pore size distribution on gas separations is demonstrated via simulations on two materials with different aging characteristics represented by evolving Gaussian functions, see Figure S8. Material A drastically ages with a large drop in pore size, intensity and variance. While Material B moderately ages with a slight drop in pore intensity and variance. The resulting CO2 and N2 separation performance is shown in Figure S9. Material A follows a typical aging trend with loss of permeability and slight gain in selectivity during aging. Material B on the other hand gains selectivity with a slight loss of

28

permeability, therefore improving with age. The model successfully captures the essential characteristics during aging. CO2 has access to more pore volume than N2 because of its smaller kinetic diameter and CO2 condenses within the pores in a denser fashion than N2.

Figure S20: Simulated pore size distributions for Material A and Material B during aging.

Figure S21: Simulated CO2/N2 selectivity for Material A and Material B during aging.

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 150

2

4

6

8

10

12

14

Pore Diameter

Po

re I

nte

nsi

ty

Material AagedMaterial Baged

10-5

10-4

10-3

10-2

10-1

10010

0

101

102

CO2 Permeability

CO

2/N

2 S

elec

tivity

Material AMaterial B

Aging

Aging

29

8. References

1. Ben, T. et al. Angew.Chem. 2009 121, 9621-9624. 2. Morisato, A. & Pinnau, I. J. Membr. Sci. 1996 121, 243-250. 3. Masuda, T., Kawasaki, M., Okano, Y. & Higashimura, T. Polym. J. 1982 14, 371-377. 4. Pinnau, I., Casillas, C. G., Morisato, A. & Freeman, B. D. J.Polym. Sci. Part B: Polym.

Phys. 1996 34, 2613-2621. 5. Du, N. et al. Macromolecules 2008 41, 9656-9662 . 6. Stern, S. A., Gareis, P. J., Sinclair, T. F. & Mohr, P. H. J. Appl. Polym. Sci. 1963 7, 2035-

2051. 7. Stern, S. A. J. Polym. Sci. Part A-2: Polym. Phys. 1968 9, 1933-1934. 8. Buckman, J. P. S. et al. 2010 21, 085702. 9. Eldrup, M.; Lightbody, D.; Sherwood, J. N., Chem. Phys 1981, 63, 51. 10. Dull, T. L.; Frieze, W. E.; Gidley, D. W.; Sun, J. N.; Yee, A. F., J. Phys. Chem. B 2001, 105

(20), 4657-4662. 11. Hill, A. J. et al. J. Membr. Sci. 2004, 243 (1-2), 37-44. 12. Freeman, B. D., Macromolecules 1999 32, 375-380. 13. Yampol'skii, Y., Pinnau, I. & Freeman, B. D. Materials Science of Membranes for Gas and

Vapor Separation. (John Wiley & Sons, Ltd, 2006). 14. Thornton, A. W. & Hill, A. J. in Membrane Gas Separation (eds Y. Yampolskii & B. D.

Freeman) (Wiley & Sons, 2010). 15. Thornton, A. W., Hilder, T., Hill, A. J. & Hill, J. M. J. Membr. Sci. 2009 336, 101-108.