1 Nanotechnology Versatile Bottom-up Nanofabrication Technique: Layer-by-Layer Assembly ~ Anuja Choubey

2 Introduction “Top-down”  Photon based Nanolithography  Electron Beam Lithography  Focused Ion Beam Lithography “Bottom-up”  Self Assembled Monolayers (SAMs)  Block Copolymers  Electrostatic Self-Assembly Layer-by-Layer Assembly (LBL) Nanofabrication Techniques

3 Background Langmuir-Blodgett (LB)  Expensive instrumentation  Not applicable for non-amphiphilic materials Self assembled Monolayer (SAM)  Not suitable for multilayer fabrication Layer-by-Layer Assembly (LBL)  Inexpensive  Simple, Easy-to-use  Enhanced modularity  Potential for greater versatility

4 How LBL works? Ariga et al., Phys. Chem. Chem. Phys., 9 (2319–2340), 2007

5 Materials Used Polyions- PAH, PDDA, PSS, PVS, PAA, PPV Proteins, DNA, Charged polysaccharides Charged inorganic substances  Colloidal nanoparticles  Clay  Nanosheets  Modified zeolite crystals. Charged supramolecular assemblies  Bolaamphiphile monolayers  Lipid bilayers  LB films  Stacked dye molecules

6 Characterization Microscopy  AFM  TEM  SEM Optical Spectroscopy Ellipsometry Quartz Crystal Microbalance (QCM)

7 Ellipsometry A. Tronin et al., Colloid Polym. Sci., 272, 1317, 1994 Quartz Crystal Microbalance

8 Applications Anti-static coating for plastics Sensors  Oxygen sensor  Glucose biosensor Light emitting diode Fuel Cells Polymer Capsules  Micro-reactors  Targeted Drug delivery

9 Fuel Cell Application

10 Formation of Polymer Capsules E.Donath et al., Angew. Chem. Int. Ed. 37, 16( ),

11 Limitations Fuzzy internal architecture Sensitive to working conditions  Humidity  Drying between cycles Future Work Synergy with other techniques  Top-down microfabrication

12 Questions?