Nanoscience at UMCP

Department of Chemistry and Biochemistry Faculty: Jeff Davis, Bryan Eichhorn, Doug English, Lyle Isaacs, Jason Kahn, Janice Reutt-Robey, Larry Sita, and Rob Walker Research Expertise: Molecular Synthesis and Self-Assembly Mesoscale Self-Assembly in Aqueous Environment Controlled Biomimetic Hierachical Organization Smart Materials and Sensors Self-Replicating Systems Supramolecular Organization of Block Copolymers Magnetic Nanostructures ‘Soft’ Materials Synthesis Chemical Derivatization of Surfaces and Interfaces Nanotubes Molecular Electronics Single Molecule Spectroscopy Characterization : NMR, AFM, STM, XPS, Single Crystal and X-ray Diffraction, MFM, SEM, TEM, SQUID, Electrospray Mass Spectroscopy, Single Molecule and Surface Optical Spectroscopies

Nanostructured and Bio-inspired Materials Mission: The controlled assembly of ‘soft’ functional nanostructures via the manipulation of ‘weak’ forces, including: hydrogen-bonding electrostatics hydrophobic effects / solvation microphase separation metal coordination supramolecular assembly Definition: The term ‘soft’ defines: environment (e.g. aqueous or interfaces) nature of subunit interactions (i.e. noncovalent, thus, both thermodynamic and kinetic assemblies possible) conditions for synthesis (e.g. low temperature production of ‘hard’ nanostructures) Range: ‘soft’ nanostructures encompass the pure chemical to the pure biological

Target Systems (1)‘Bionics’ Self-replicating Self-repairing Nano muscles and nanomechanical devices Nano pores and channels Vesicles and capsules Motors and Actuators Frameworks and Armature Micron-scale assembles from nanoscale constructs (2) ‘Soft’ Assembly of ‘Hard’ Nanostructures Low temperature and shape-selective routes to dots, nanotubes, whiskers and asymmetric shapes of carbon, semiconductors, and metal Templated assembly of 2- and 3-D arrays of hard nanostructures for device fabrication Metastable structures

(3) Surfaces and Interfaces: Control of electron transport Control of solute / surface interactions Nanoporous membranes Nanolithography Electrochemical and Optical sensors Platforms for hierarchal organization of biostructures and cells. Target Systems

Artificial Ion Channels via Self-Assembly Davis Group Oxygen-Rich Pore Hydrophobic Exterior Crystal Structure of a Filled K + Ion Channel Hydrogen-Bonded G Quartet Selective K + Ion Transport Across Bilayer Membrane

Davis Group pH pulse Triton X- 100 NaCl Na 2 SO 4 Calix Amide 5 s 1 pA closed opene d Artificial Ion Channels via Self-Assembly Aggregation in the presence of HClSelective Transport of Cl - AnionFormation of Ion Channels Calixarene tetramide – potential antibiotic

Hydrophobic Self-Assembly in Water Isaacs Group Self-Complementary Facile Amphiphiles Crystal StructureAnalytical UltracentrifugationSolution NMR Form Dimers in Aqueous Environment

Triggered Enantiomeric Self-Recognition Isaacs Group

Microscale (cannot easily functionalize) Nanoscale Molecules (no bulk properties) Microscale Metastable Bulk Materials retain bulk properties retain molecular (kinetic) control cation and anion metathesis over short distances low temperature reactions / functional groups precursors Nanostructured Materials via “Soft” Synthesis Eichhorn Group

10 nm ~20 nm metastable hexagonal nanocrystal Electron diffraction of nanocrystal Organic / Inorganic Metastable Materials Refractory ZrN layer  ( -CN) layer ZrN(CN) x Nanoscale Synthesis of Functionalized Refractories

Molecular Electronics Sita Group Demonstration of Two-State SystemConduction Physics of Single Molecules Tapping Mode AFM Image Concept

Supramolecular Polymer Chemistry Metal Nanostructures Au nanocrystals (1 nm dia) Sita Group Architectural Control Cu nanostructures (20 nm wide)