Understanding Molecular Interactions within Chemically Selective Layered Polymer Assemblies

Gary J. Blanchard

关键词: ADSORPTION;    CHEMISTRY;    COPOLYMERIZATION;    CROSS-LINKING;    DEPOLARIZATION;    DEPOSITION;    ETHERS;    FLUORESCENCE;    GOLD;    GRAVIMETRY;    IMPEDANCE;    KINETICS;    LIFETIME;    MICROBALANCES;    MORPHOLOGY;    ORIGIN;    POLYMERS;    PROBES;    QUARTZ;    SHEAR;    SOLVENTS;    THICKNESS;    VISCOSITY interfacial chemical selectivity;    ultrathin polymer films;   

DOI  :  10.2172/958086
RP-ID  :  DOE/ER/15001-1
PID  :  OSTI ID: 958086
Others  :  TRN: US201004%%410

学科分类：化学（综合）

美国|英语

来源: SciTech Connect

【 摘 要 】

This work focuses on two broad issues. These are (1) the molecular origin of the chemical selectivity achieved with ultrathin polymer multilayers, and (2) how the viscoelastic properties of the polymer layers are affected by exposure to solvent and analytes. These issues are inter-related, and to understand them we need to design experiments that probe both the energetic and kinetic aspects of interfacial adsorption processes. This project focuses on controling the chemical structure, thickness, morphology and sequential ordering of polymer layers bound to interfaces using maleimide-vinyl ether and closely related alternating copolymerization chemistry and efficient covalent cross-linking reactions that allow for layer-by-layer polymer deposition. This chemistry has been developed during the funding cycle of this Grant. We have measure the equilibrium constants for interactions between specific layers within the polymer interfaces and size-controlled, surface-functionalized gold nanoparticles. The ability to control both size and functionality of gold nanoparticle model analytes allows us to evaluate the average “pore size” that characterizes our polymer films. We have measured the “bulk” viscosity and shear modulus of the ultrathin polymer films as a function of solvent overlayer identity using quartz crystal microbalance complex impedance measurements. We have measured microscopic viscosity at specific locations within the layered polymer interfaces with time-resolved fluorescence lifetime and depolarization techniques. We combine polymer, cross-linking and nanoparticle synthetic expertise with a host of characterization techniques, including QCM gravimetry and complex impedance analysis, steady state and time-resolved spectroscopies.