1. CHE5480 Summer 2005 Dendrimers and Nanofluidics

2. Nanostructured Materials: Carbon nanotubes Aerogels Zeolites Dendrimers Self-assembled monolayers Nanoparticles Nanowires NEMS, etc.

3. Example of Nanostructures : Starburst Dendrimers

4. What is a dendrimer? Branched polymers ( dendron = tree in Greek) = 3 (Nitrogen) What is a dendrimer? Branched polymers ( dendron = tree in Greek) Functionality = 3 (Nitrogen)

6. Generations of Dendrimers 2 nd gen. 4 th gen. 5 th gen.

8. PAMAM Dendrimer (polyamidoamine) Alternating (B)-AB-AB-AB-... Ethylenediamine (B) H 2 N-C-C-NH 2 Methylacrylate (A) C=C-CO-OCH 3

9. PAMAM Moieties: Acrylate Diamine NH 3 or Diamine

11. Size of PAMAM Dendrimers Generation M.W. Angstrom (dia.) End Gps (1 nm = 10 Angstroms)

12. Equivalent Sizes with Cells:

13. Applications of Dendrimers Gas and chemical sensors Catalysts Drug delivery and gene therapy Surface modifiers (tribology, and information storage) Bio compatible materials Electronic devices and antennae

14. Nanofluidics: Flows in channels of nanometer dimension

15. Nanofluidics : Examples of MEMS & NEMS : (Micro- & Nano-electromechanical systems) Lieber (Harvard)

16. (“Laboratory-on-a chip”) Lieber (Harvard) MEMS

17. Flow behavior in nanofluidics:

18. Flow behavior in nanofluidics: (2) LOCOMOTION? difficult to make fluid flow in small channels. Driving forces: 1. Pressure 2. Surface-capillary force 3. Electric (electroosmotic, electrophoretic, electrohydrodynamic, electrowetting), and magnetic (magnetohydrodynamic) 4. Sound—acoustic 5. Centrifuge (rotation)

19. Making Circuitry by Nanofluidics: (Lieber, Harvard) Purpose: using viscous flow in nanochannels. to orient and assemble nanowires (to make logical circuitries). Note: at nanoscale, the surface effects are large (due to large surface-to-volume ratio). Thus viscous forces dominate in the flow.

20. (1) Make a mold of channels (PDMS-polydimethylsiloxane). (2) Disperse nanowires (GaP, InP, Si) in ethanol, the carrier solvent. (3) Flow the suspension through the nanochannels.

21. SEM images of aligned nanowires. Charles Lieber (Harvard)--2 SEM: bar = 2 μm bar = 50 μm

22. Nanocircuitries : Examples of NEMS Lieber (Harvard)

25. hydrophobic surfaces Harvard OTS

26. What happens to the flow when the interface is hydrophobic? --Slip Velocity at wall is 10% of the center (NOT zero, i.e. Slip). This increases the total volumetric flow. 2002 Phys. Fluids

27. On what theories to use for nanoscale flows?

30. 2. Nanostructured materials: Gas adsorption in dendrimers

31. Dendrimer: PAMAM

32. 2. Nanostructured materials: Gas adsorption in dendrimers