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Adham Ahmed - uni of liverpool

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Adham Ahmed - uni of liverpool

  1. 3. New drugs medicinal chemistry of antimalarial and anticancer drugs. 'Dry Water' technology potential for commercial applications in the storage and transportation of gases such as methane and carbon dioxide, as well as in green catalysis Superficially porous silica
  2. 4. <ul><li>Uniform silica microspheres </li></ul><ul><li>Formation of Organic Nanoparticles by Freeze-Drying and Their Controlled Release </li></ul><ul><li>Freeze-Align and Heat-Fuse: Microwires and Networks from Nanoparticle Suspensions </li></ul><ul><li>Systematic tuning of pore morphologies and pore volumes in macroporous materials by freezing </li></ul><ul><li>Porous silica spheres in macroporous structures and on nanofibres </li></ul><ul><li>Hierarchically porous silica monoliths with tuneable morphology, porosity, and mechanical stability </li></ul><ul><li>Surface pattern for cell-growth </li></ul><ul><li>Novel aligned silica monolith </li></ul><ul><li>A new superficially porous silica particles </li></ul>H. Zhang, J. Lee, A. Ahmed, I. Hussain, A.Cooper , Angew. Chem. Int. Ed. 2008 , 47 A. Ahmed, P. Myers, H. Zhang, Ind. Eng. Chem. Res. 2010 , 49, 602 A. Ahmed, N. Grant, L. Qian, H. Zhang, Nanosci. Nanotechnol. Lett. 2009, 1, 185 A. Ahmed, P. Myers, H. Zhang, J. Chem. Mater. 2011 , in press L. Qian, A. Ahmed, H. Zhang, Chem. Mater. 2011 , in press 4µm 300nm 15µm 40µm 30µm
  3. 5. Outline <ul><li>How to make hierarchically porous silica beads using polyHIPEs </li></ul><ul><li>Controlling the growth of silica particles </li></ul><ul><li>Changing the particles size and physical properties </li></ul><ul><li>Silica spheres on other porous structures </li></ul>3µm 2µm
  4. 6. Emulsion Templated Porous Polymers (PolyHIPEs) <ul><li>Poly(High Internal Phase Emulsion) </li></ul><ul><li>HIPE: high droplet phase volume, >70% </li></ul><ul><li>Monomeric continuous phase </li></ul>Barby & Haq, Eur. Pat. 0,060,138 (1982) N. Cameron, Polymer , 2005 , 46 , 1439
  5. 7. PolyHIPE (polyacrylamide) Beads Dropwise addition of HIPE to long column of hot oil (sedimentation polymerisation) H. Zhang, A. Cooper, Chem. Mater. 2002 , 14 , 4017
  6. 8. Adsorption of Silica Colloids Structure collapsed 50µm 5µm 2µm Embedded into the macropore walls Silica colloids -Poly(acrylamide) composite
  7. 9. Silica Synthesis in PAM Beads H. Zhang, A. Cooper, Chem. Mater. 2004 , 16 , 4245 Microscopic silica-gel coating Silica gel -Poly(acrylamide) composite Acidic conditions 25µm 5µm 50µm
  8. 10. Synthesis of Silica Colloids in PAM Beads Base H 3 N : 24 hrs 24 hrs Soaked Modified Stöber synthesis Silica precursor with organic template CTAB and PVA A. Ahmed, P. Myers, H. Zhang, Ind. Eng. Chem. Res. 2010 , 49, 602 Silica growth
  9. 11. silica nanospheres Silica microspheres 30µm Void diameter 10 – 30 µm Interconnecting (window) Internal pore structure External pore structure A. Ahmed, P. Myers, H. Zhang , Phil. Trans. R. Soc. A 2010 , 368, 4351 2µm 300µm 30µm
  10. 12. Template removal by calcination 30µm 1mm 2µm 5µm
  11. 13. d- spacing 7.1nm 13.9µm 10.7nm 1.9nm Surface area = 220 m 2 /g
  12. 14. Increasing silica precursor concentration <ul><li>Doubling TEOS amount </li></ul><ul><li>Increased mechanical stability </li></ul><ul><li>Lower surface area 53.6 m 2 /g </li></ul><ul><li>A large portion of nanoparticles </li></ul><ul><li>(approx. 200 nm) </li></ul>2µm 20µm Thicker pore wall ~10nm 4µm
  13. 15. 17.2µm 12.0nm Surface area = 116 m 2 /g Without PVA and CTAB Without CTAB Control the silica spheres size Surface area = 165 m 2 /g 2µm 30 µm 50 µm 2µm
  14. 16. d- spacing 7.1nm 11.3µm 1.9nm Surface area = 729 m 2 /g d- spacing 2.5nm Tuning silica beads surface area and porosity 20 µm 10 µm
  15. 17. Silica-PAM composite beads as a template H. Zhang, G. Hardy, M. Rosseinsky, A.Cooper, Adv. Mater. 2003 , 15, 78
  16. 18. 3.9µm 7.6nm Surface area = 247 m 2 /g 4µm 100 µm Internal pore structure 50 µm external pore structure 2µm
  17. 19. Porous Structures by Freezing method Frozen LN Polymer solution Freeze-dried nanofibers Microfibers Monolith Polymer %wv Microsheets
  18. 20. Sub-Micron chitosan structures 0.1% wv 1% wv 1µm 200µm L. Qian, A. Ahmed, H. Zhang ., J. Mater. Chem. , 2009 , 19, 5212 L. Qian, E. Willneff, H. Zhang, Chem. Commun. 2009 , 3946
  19. 21. Silica Spheres on Sub-Micron chitosan structures A. Ahmed, P. Myers, H. Zhang , Phil. Trans. R. Soc. A 2010 , 368, 4351 Chitosan sheet-like structure as a template Chitosan fibers structure as a template 1% wv 0.1% wv 0.05% wv 1mm 1µm 5µm 1µm 10µm 2µm 2µm
  20. 22. 2.2nm Surface area = 169 m 2 /g d- spacing 4.85nm 60µm 3.5nm Template removal by calcination 2µm 1µm
  21. 23. Fe–sodium carboxymethyl cellulose composite fibre Surface area = 291 m 2 /g SCMC fibres modified with iron trichloride α -Fe 2 O 3 fibres (haematite) Fe 2 O 3 – Silica composite Calcined 600 o C Silica synthesis 0.1% wv 5µm 5µm 1µm
  22. 24. Conclusions <ul><li>Highly porous silica beads </li></ul><ul><li>Controlling the particles size, surface area and porosity </li></ul><ul><li>Silica spheres on sub-micron polymer and metal oxide structures </li></ul>1mm 5µm
  23. 25. Acknowledgements <ul><li>Supervisors </li></ul><ul><ul><li>Dr. Haifei Zhang </li></ul></ul><ul><ul><li>Prof. Peter Myers </li></ul></ul><ul><li>ThermoFisher </li></ul><ul><ul><li>Dr. Harald Ritchie (development director) </li></ul></ul><ul><li>CMD </li></ul><ul><ul><li>Rob Clowes </li></ul></ul><ul><ul><li>Elizabeth Willneff (Manchester University) </li></ul></ul><ul><ul><li>Lei Qian (University of Singapore) </li></ul></ul>

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