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Polymer infiltration is studied in a bicontinuous, nanoporous gold (NPG) scaffold. For poly(2-vinylpyridine) (P2VP) with molecular weights (M_w) from 51k to 940k Da, infiltration is investigated in a NPG with fixed pore radius (R_p= 34 nm) under moderate confinement (Γ = R_g/R_p ) 0.18 to 0.78. The time for 80% infiltration (τ_(80%)) scales as M_w^1.43, similar to PS, but weaker than bulk behavior. Infiltration of P2VP is slower than PS due to stronger P2VP-wall interactions resulting in a physisorbed P2VP layer. This interpretation is supported by the similar scaling of τ_(80%) for P2VP and PS, as well as Molecular Dynamics (MD) simulations. Simulations show that infiltration time scales as M_w^1.43and that infiltration slows as the polymer-wall attraction increases. As M_w increases, the effective viscosity transitions from greater than to less than the bulk viscosity due to pore narrowing and a reduction entanglement density. These studies provide new insight for polymer behavior under confinement and a new route for preparing nanocomposites at high filler loadings. 

One of the biggest challenges in the field of polymer nanocomposites (PNCs) is to disperse high nanofiller loadings into the polymeric matrix. The high loading and uniform dispersion are limited by the unfavored polymer/nanofiller thermodynamics and the tendency for nanofiller to aggregate. In this thesis, these are circumvented by using nanoporous gold (NPG) as a scaffold for polymers to fill. The ultra-high loading (>50 vol%) is achieved by infiltrating polymer melts into NPG to produce a polymer infiltrated nanoporous gold (PING) composite. This novel composite provides promises for the next generation advanced materials for coating, optical sensors, actuators, and batteries. This thesis contributes to the better understanding of polymer kinetics under moderate confinement by varying the interfacial energy between polymer and pore wall and investigating the temperature dependence of infiltration. Confinement enhances polymer kinetics while decreasing the infiltration time dependence on Mw due to the combined effect of loss in entanglement and adsorbed chain fraction. When polymer and the wall interfacial energy is stronger, a physiosorbed layer forms, resulting in slower kinetics compared to that for weaker interfacial energy. The temperature dependence of the polymer kinetics inside NPG follows the bulk WLF behavior at lower confinement degrees, while the kinetics deviate from the bulk WLF at higher confinement levels due to the decrease in thermal expansion coefficient. Those fundamental studies on polymer kinetics enable the optimization of preparing PING composites for the use of industrial scale applications and encourage additional studies such as ion conductivities of PING. The optical properties study established UV-Vis spectroscopy as a new approach to track polymer kinetics while simultaneously broadening the potential PING applications to optically responsive membranes. This thesis presents a pathway of fabricating PING composite while kinetics studies as well as the optical study enable scientists to better understand polymers behavior under confinement and advance the toolbox for creating interconnected polymer/filler systems at high filler concentrations. 

Because 3D batteries comprise solid polymer electrolytes (SPE) confined to high surface area porous scaffolds, the interplay between polymer confinement and interfacial interactions on total ionic conductivity must be understood. This paper investigates contributions to the structure-conductivity relationship in poly(ethylene oxide) (PEO)–lithium bis(trifluorosulfonylimide) (LiTFSI) complexes confined to microporous nickel scaffolds. For bulk and confined conditions, PEO crystallinity decreases as the salt concentration (Li+:EO (r) = 0.0.125, 0.0167, 0.025, 0.05) increases. For pure PEO and all r values except 0.05, PEO crystallinity under confinement is lower than in the bulk, whereas glass transition temperature remains statistically invariant. At 298 K (semicrystalline), total ionic conductivity under confinement is higher than in the bulk at r = 0.0167, but remains invariant at r = 0.05; however, at 350 K (amorphous), total ionic conductivity is higher than in the bulk for both salt concentrations. Time–of–flight secondary ion mass spectrometry indicates selective migration of ions towards the polymer–scaffold interface. In summary, for the 3D structure studied, polymer crystallinity, interfacial segregation, and tortuosity play an important role in determining total ionic conductivity and, ultimately, the emergence of 3D SPEs as energy storage materials. 

Polymer infiltrated nanoporous gold is prepared by infiltrating polymer melts into a bicontinuous, nanoporous gold (NPG) scaffold. Polystyrene (PS) films with molecular weights (Mw) from 424 to 1133 kDa are infiltrated into a NPG scaffold (∼120 nm), with a pore radius (Rp) and pore volume fraction of 37.5 nm and 50%, respectively. The confinement ratios (Γ=RgRp) range from 0.47 to 0.77, suggesting that the polymers inside the pores are moderately confined. The time for PS to achieve 80% infiltration (τ80%) is determined using in situ spectroscopic ellipsometry at 150 °C. The kinetics of infiltration scales weaker with Mw, τ80%∝Mw1.30±0.20, than expected from bulk viscosity Mw3.4. Furthermore, the effective viscosity of the PS melt inside NPG, inferred from the Lucas–Washburn model, is reduced by more than one order of magnitude compared to the bulk. Molecular dynamics simulation results are in good agreement with experiments predicting scaling as Mw1.4. The reduced dependence of Mw and the enhanced kinetics of infiltration are attributed to a reduction in chain entanglement density during infiltration and a reduction in polymer–wall friction with increasing polymer molecular weight. Compared to the traditional approach involving adding discrete particles into the polymer matrix, these studies show that nanocomposites with higher loading can be readily prepared, and that kinetics of infiltration are faster due to polymer confinement inside pores. These films have potential as actuators when filled with stimuli-responsive polymers as well as polymer electrolyte and fuel cell membranes. 

Phytoglycogen nanoparticles are soft, naturally-derived nanomaterials with a highly uniform size near 35 nm. Their interior is composed of a highly-branched polysaccharide core that contains more than 200% of its dry mass in water. In this work, we measure the translocation of phytoglycogen particles by observing blockade events they create when occluding solid-state nanochannels with diameters between 60 and 100 nm. The translocation signals are interpreted using Poisson–Nernst–Planck calculations with a “hardness parameter” that describes the extent to which solvent can penetrate through the interior of the particles. Theory and experiment were found to be in quantitative agreement, allowing us to extract physical characteristics of the particles on a per particle basis.