Dendrimers and Nanofluidics: Innovations in Nanostructured Materials
This text explores the fascinating realms of dendrimers and nanofluidics within nanostructured materials. Dendrimers, particularly the PAMAM type, are branched polymers known for their functionality across various generations. Applications span gas sensors, drug delivery, and electronic devices. Additionally, nanofluidics governs the flow in nano-sized channels, utilizing principles like electroosmotic flow and capillary forces. The document further details methods for creating nanocircuitries using nanowires and discusses the implications of surface effects in nanoscale fluid dynamics.
Dendrimers and Nanofluidics: Innovations in Nanostructured Materials
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Presentation Transcript
CHE5480 Summer 2005 Dendrimers and Nanofluidics
Nanostructured Materials: • Carbon nanotubes • Aerogels • Zeolites • Dendrimers • Self-assembled monolayers • Nanoparticles • Nanowires • NEMS, etc.
What is a dendrimer? Branched polymers(dendron = tree in Greek)Functionality= 3 (Nitrogen)
Generations of Dendrimers Your Text Here
Generations of Dendrimers 2nd gen. 5th gen. 4th gen.
PAMAM Dendrimer (polyamidoamine) • Alternating (B)-AB-AB-AB-... • Ethylenediamine (B) • H2N-C-C-NH2 • Methylacrylate (A) • C=C-CO-OCH3
PAMAM Moieties: Diamine Acrylate NH3 or Diamine
Size of PAMAM DendrimersGeneration M.W. Angstrom (dia.) End Gps (1 nm = 10 Angstroms)
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
Nanofluidics :Examples of MEMS & NEMS: (Micro- & Nano-electromechanical systems) Lieber (Harvard)
(“Laboratory-on-a chip”) Lieber (Harvard) MEMS
Flow behavior in nanofluidics: (2) • LOCOMOTION? difficult to make fluid flow in small channels. • Driving forces: • Pressure • Surface-capillary force • Electric (electroosmotic, electrophoretic, electrohydrodynamic, electrowetting), and magnetic (magnetohydrodynamic) • Sound—acoustic • Centrifuge (rotation)
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.
(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.
SEM images of aligned nanowires.Charles Lieber (Harvard)--2 SEM: bar = 2 μm bar = 50 μm
Nanocircuitries :Examples of NEMS Lieber (Harvard)
hydrophobic surfaces OTS Harvard
What happens to the flow when the interface is hydrophobic? --Slip 2002 Phys. Fluids Velocity at wall is 10% of the center (NOT zero, i.e. Slip). This increases the total volumetric flow.
