Supporting Information

Transcription

1 Supporting Information Towards an understanding of the microstructure and interfacial properties of PIMs/ZIF-8 mixed matrix membranes. Marvin Benzaqui, Rocio Semino, Nicolas Menguy, Florent Carn, Tanay Kundu, Jean- Michel Guigner, Neil B. McKeown, Kadhum J. Msayib, Mariolino Carta, Richard Malpass-Evans, Clément Le Guillouzer, Guillaume Clet, Naseem A. Ramsahye Christian Serre, Guillaume Maurin, Nathalie Steunou,* Institut Lavoisier de Versailles, UMR CNRS 8180, Université de Versailles St Quentin en Yvelines, Université Paris Saclay, 45 avenue des Etats-Unis Versailles Cedex. France. Institut Charles Gerhardt Montpellier UMR 5253 CNRS, Universite de Montpellier, Place E. Bataillon, Montpellier Cedex 05, France Institut de Minéralogie de Physique des Matériaux et de Cosmochimie, UMR 7590 CNRS UPMC Univ Paris 06 MNHN IRD Sorbonne Universités, 4 place jussieu, Paris cedex 05, France. Laboratoire Matière et Systèmes Complexes (MSC), UMR CNRS 7057, Université Paris Diderot, Bât. Condorcet, 10 rue A. Domon et L. Duquet, Paris, France. School of Chemistry, University of Edinburgh, Joseph Black Building, West Mains Road, Edinburgh EH9 3JJ, U. K. Normandie Univ, ENSICAEN, UNICAEN, CNRS, Laboratoire Catalyse et Spectrochimie, Caen, France. nathalie.steunou@uvsq.fr S-1

2 I- Characterization of ZIF-8 NPs and polymers (i. e. PIM-1 and PIM-EA-TB) Figure S1. Full pattern matching of ZIF-8 NPs; a = Å, V = Å 3, space group: I-43m; experimental data in blue and calculated pattern in red. S-2

3 V a /cm 3 (STP) g -1 wt% Temperature C ZIF-8 nanoparticles Figure S2. Thermogravimetric analysis of ZIF-8 NPs 800 ZIF-8 nanoparticles ,0 0,5 1,0 p/p 0 Figure S3. N 2 sorption isotherm of ZIF-8 NPs performed at 77K S-3

4 Count 15 (c) Particle size (nm) Figure S4. (a) SEM, (b) TEM images and (c) size distribution of ZIF-8 NPs. S-4

5 I (a.u.) Intensity (%) g.l g.l Size (r.nm) Figure S5. Size distribution (radius in nm) of ZIF-8 NPs at 0.1 and 1 g L -1 in THF by DLS. 1 0,1 0,01 1E-3 0,01 0,1 q (A -1 ) Figure S6. SAXS curve of ZIF-8 dispersed in THF at [ZIF-8] = 0.01 g L -1. S-5

6 Intensity (%) Intensity (%) Intensity (%) Size (r.nm) Size (r.nm) Size (r.nm) Figure S7. Size distribution (radius in nm) of PIM-1 in THF at 4 g L -1 (top) and at 10 g L -1 (middle) by DLS and PIM-EA-TB in CHCl 3 at 10 g L -1 (bottom). S-6

7 II- Characterization of ZIF-8/PIM-1 membranes 2Θ Figure S8. X-ray diffraction pattern of ZIF-8 NPs and ZIF-8/PIM-1 membranes with different ZIF-8 NPs loading (10, 20 and 40 wt%). ZIF-8/PIM-1 0/100 20/ /60 100/ Figure S9. FT-IR spectra of ZIF-8, PIM-1 and ZIF-8/PIM-1 membranes with different ZIF-8 NPs loading Wavenumber (cm -1 ) S-7

8 Figure S C CP MAS of ZIF-8, PIM-1 and ZIF-8/PIM-1 membranes with different ZIF- 8/PIM-1 weight ratio (40/60, 20/80) S-8

9 Figure S11. (a) SEM image of ZIF-8/PIM-1 membranes (ZIF-8/PIM-1 = 10/90 wt%, no ultrasonication) and (b-d) elemental mapping of (b) carbon, (c) oxygen and (d) zinc by SEM- XEDS for the rectangular area indicated by the white box in panel (b). S-9

10 Spectrum 11 Spectrum 12 Spectrum 13 Spectrum 14 Spectrum 15 Spectrum 16 Spectrum 17 Spectrum 18 (b) Spectrum Spectrum Spectrum Spectrum Spectrum Spectrum Spectrum Spectrum C O Zn Figure S12. (a) cross-section SEM image of ZIF-8/PIM-1 MMM (ZIF-8 of 10 wt%, ultrasonication) and (b) XEDS analysis of different parts of the membranes indicated in SEM image (a). S-10

11 Figure S13. (a) SEM image of ZIF-8/PIM-1 membranes (ZIF-8/PIM-1 = 20/80 wt%, ultrasonication) and (b-d) elemental mapping of (b) carbon, (c), oxygen and (d) zinc by SEM- XEDS for the rectangular area indicated by the white box in panel (a). S-11

12 III- Characterization of ZIF-8/PIM colloidal suspensions (a) (b) Figure S14. (a,b) HAADF-STEM images of ZIF-8/PIM-1 at [ZIF-8]= 0.1 g.l -1 and ZIF- 8/PIM-1 = 20/80 wt%. For these solutions, the excess of polymer was removed by centrifugation. For (b), the solution was deposited on the carbon grid after ultrasonication. S-12

13 Figure S15. (a,b) HAADF-STEM images of ZIF-8/PIM-1 colloidal suspensions at ZIF- 8/PIM-1 =20/80 wt% [ZIF-8] = 1 g L -1. TEM observations are performed on solutions that were ultrasonicated before casting. S-13

14 Figure S16. TEM bright field and HAADF-STEM images of ZIF-8/PIM-EA-TB colloidal suspensions at [ZIF-8] = 0.1 g L -1 and different ZIF-8/PIM-EA-TB weight ratios: (a), (b), (c): 50/50; (d), (e), (f): 20/80. For all these solutions, the excess of polymer was removed by centrifugation. S-14

15 Table S1. Characteristic parameters of the different components. d and ρ stand for mass density and SAXS scattering length density respectively. Name Formula d (g.cm -3 ) ρ (x 10-6 Å -2 ) ZIF-THF [Zn(C 4 H 6 N 2 ) 2 ] 2 C 4 H 8 O THF C 4 H 8 O PIM-1 C 29 H 20 N 2 O IV- Molecular Modeling of ZIF-8/PIMs interfacial structure. PIM-EA-TB model Figure S17 shows a picture of the PIM-EA-TB monomer. The atom types along with the non-bonded parameters are detailed in Table S2. Figure S17. Scheme of PIM-EA-TB polymer. S-15

16 Table S2. Atom types, charges and LJ parameters for the PIM-EA-TB model. Atom type Number (see Fig S17) ε ii (kcal/mol) σ ii (Å) q i (e) CAA 3,6,11, CAB 1,2,12,13 4,5,8,9 CH 2 15,16 19, Me (CH 3 ) 17, CH0 7, NA3 20, CHN NA1 Terminal HA1 Terminal The polymer model consisted of 9 polymer chains between 10 and 20 monomers each, with a total of 112 monomers, a number that is similar to the one for the PIM-1 model we previously considered for the study of the ZIF-8/PIM-1 composite. Regarding the chain terminations, the following procedure was employed: (1) the phenyl termination was capped by adding an NH 2 group to atom 2 and by changing the atom type of atom 1 from CAB (aromatic carbon atom) to CAA (aromatic CH group). (2) for the nitrogen side termination, atoms 19, 20, 21, 22 and 23 were removed, an NH 2 group was added to atom 13 and the atom type of atom 12 was changed from CAB to CAA. These terminations were chosen so that the model resembles the real polymer. Interface generation The ZIF-8/PIM-EA-TB interface was generated as follows: S-16

17 (1) the [011] ZIF-8 surface model was chosen to build the interface, since this one had the lowest energy amongst those we have previously explored. 1 (2) The model PIM-EA-TB was generated in a box of dimensions 50 Å x 50 Å x 150 Å, and then two empty boxes were added in the z direction, resulting in a box of dimensions 50 Å x 50 Å x 400 Å. (3) PIM-EA-TB was equilibrated using a 21-steps equilibration scheme as proposed by Hofmann and collaborators. 2 Seven cycles of three simulations each were performed. The j-th cycle consisted of: (i) NVT ensemble, T = 600 K; (ii) NVT ensemble, T = 300 K; and (iii) NPT, T = 300 K, P = Pj (P 1 = 1, P 2 = 30, P 3 = 50, P 4 = 25, P 5 = 5, P 6 = 0.5, P 7 = 0.001, all values in kbar). The same set of parameters was previously used to equilibrate PIM-1. 3 (4) the coordinates of PIM-EA-TB were unwrapped in the z direction, and then the ZIF-8 surface was added, by putting the two simulation boxes together in the z direction. Again, a 21-steps equilibration was performed, but this time, the constant pressure simulations were carried out so that the cell could only change its volume by variations of the z length. (5) this procedure has been repeated for ten different PIM-EA-TB configurations, and production runs of 10 ns long were obtained in the NVT ensemble, using Berendsen thermostat with a relaxation time of 0.1 ps. 4 ZIF-8/PIM-EA-TB analysis: complementary results Figure S18. Radial distribution functions for the ZIF-8/PIM-EA-TB interface model, for the pairs (OH) ZIF-8 X PIM-EA-TB. Results obtained from four different MD runs. X PIM-EA-TB sites are indicated in red in the inset scheme for each panel. S-17

18 Figure S19. (a) Radial distribution function for the ZIF-8/PIM-1 interface model, for the pair (NH) ZIF-8 N PIM-1. Results obtained from four different MD runs. (b) Scheme of the interaction. The porosity of the polymer phase in contact with ZIF-8 was studied according to two different methodologies: (i) the v_connect method, 5 and (ii) the one reported by Bhattacharya et al. 6 In the first one, the voids within the polymer were determined by superimposing a 3D grid of 0.7 Å, and assigning 1 to the cubes where atoms were found and 0 if the cubes were empty. The 0 labeled regions are then sampled by a positronium or nitrogen sized particle (1.1 Å or 1.82 Å). The second methodology, computes the distribution of pores taking into account a sphere whose radius increases in a given position of space, up to the point where it overlaps with the polymer atoms. Results for these kinds of analyses for one representative ZIF-8/PIM-EA-TB interface configuration are plotted in Figure S20. S-18

19 Figure S20. Pore number and free volume of the pores as a function of their radius computed for a representative configuration for ZIF-8/PIM-EA-TB (top and middle panels respectively). Red = nitrogen sized probe, black = positronium sized probe. The bottom panels present results of the pore size distribution as a function of the radius of a growing probe. On the left, region A, on the right, region B. References: 1 Semino, R.; Ramsahye, N. A.; Ghoufi, A.; Maurin, G. Microscopic Model of the Metal- Organic Framework/Polymer Interface : A First Step toward Understanding the Compatibility in Mixed Matrix Membranes. ACS Appl. Mater. Interfaces 2016, 8, Hofmann, D.; Fritz, L.; Ulbrich, J.; Schepers, C.; Böhning, M. Detailed-Atomistic Molecular Modeling of Small Molecule Diffusion and Solution Processes in Polymeric Membrane Materials. Macromol. Theory Simul. 2000, 9, Larsen, G. S.; Lin, P.; Hart, K. E.; Colina, C. M. Molecular Simulations of PIM-1-like Polymers of Intrinsic Microporosity. Macromolecules 2011, 44, S-19

20 4 Berendsen, H. J. C.; Postma, J. P. M.; van Gunsteren, W. F.; DiNola, A.; Haak, J. R. Molecular Dynamics with Coupling to an External Bath. J. Chem. Phys. 1984, 81, Hofmann, D.; Heuchel, M.; Yampolskii, Y.; Khotimskii, V.; Shantarovich, V. Free Volume Distributions in Ultrahigh and Lower Free Volume Polymers: Comparison between Molecular Modeling and Positronium Lifetime Studies. Macromolecules 2002, 35, Bhattacharya, S.; Gubbins, K.E. Fast Method for Computing Pore Size Distributions of Model Materials. Langmuir 2006, 22, S-20