130 research outputs found
Synthetic and bio-hybrid nanoscale layers with tailored surface functionalities
Abstract We examine the prospective routes for the design of synthetic/biomacromolecular/inorganic film assemblies for photothermal cell based on biomimetic approach. We demonstrate examples of channel proteins immobilized onto surfaces of silicon single crystals modified with Langmuir-Blodgett and self-assembled monolayers. These proteins can be immobilized in intact, closed-pore conformation. Their state within photosensitive monolayers can be controlled by the photoisomerization reaction triggered by UV light
Atomic Force Microscopy and Optical Studies of Organic Thin Films with Hydrogen-Bonded Networks
Brewster angle microscopy and atomic force microscopy were used to characterize the surface morphology of thin films in situ or after transfer onto solid supports. Two acids were studied, differing in carboxylic acid head groups, resulting in significantly different morphological features for thin films formed from these two amphiphiles on a Langmuir trough. Differences in self-assembly and domain sizes were correlated with the formation of hydrogen-bonded networks. The influence of surface hydrophobicity or hydrophilicity during deposition on morphology was also characterized, with spherulitic features appearing in some samples
Geomechanical stability of the caprock during CO2 sequestration in deep saline aquifers
8 páginas, 5 figuras.Sequestration of carbon dioxide (CO2) in deep saline aquifers has emerged as a mitigation strategy for reducing greenhouse gas emissions to the atmosphere. The large amounts of supercritical CO2 that need to be injected into deep saline aquifers may cause
large fluid pressure buildup. The resulting overpressure will produce changes in the effective stress field. This will deform the
rock and may promote reactivation of sealed fractures or the creation of new ones in the caprock seal, which could lead to escape
paths for CO2. To understand these coupled hydromechanical phenomena, we model an axisymmetric horizontal aquifer-caprock
system. We study plastic strain propagation patterns using a viscoplastic approach. Simulations illustrate that plastic strain may
propagate through the whole thickness of the caprock if horizontal stress is lower than vertical stress. In contrast, plastic strain
concentrates in the contact between the aquifer and the caprock if horizontal stress is larger than vertical stress. Aquifers that
present a low-permeability boundary experience an additional fluid pressure increase once the pressure buildup cone reaches the
outer boundary. However, fluid pressure does not evolve uniformly in the aquifer. While it increases in the low-permeability
boundary, it drops in the vicinity of the injection well because of the lower viscosity of CO2. Thus, caprock stability does not get
worse in semi-closed aquifers compared to open aquifers. Overall, the caprock acts as a plate that bends because of pressure
buildup, producing a horizontal extension of the upper part of the caprock. This implies a vertical compression of this zone,
which may produce settlements instead of uplift in low-permeability (k≤10-18 m2) caprocks at early times of injection.V.V. would like to acknowledge the Spanish Ministry of Science and Innovation (MIC) for financial support through the “Formación de Profesorado Universitario” program. V.V. also wishes to acknowledge the “Colegio de
Ingenieros de Caminos, Canales y Puertos – Catalunya” for their financial support. This project has been funded by the Spanish Ministry of Science and Innovation through the project CIUDEN (Ref.: 030102080014), and through the MUSTANG project, from the European Community’s Seventh Framework Programme FP7/2007-2013 under grant agreement nº 227286.Peer reviewe
NIRT: Bioinspired nanomembranes for multifunctional sensors
Issued as final reportNational Science Foundation (U.S.
Liquid-crystalline processing of highly oriented carbon nanotube arrays for thin-film transistors
We introduce a simple solution-based method for the fabrication of highly oriented carbon nanotube (CNT) arrays to be used for thin-film transistors. We exploit the liquid-crystalline behavior of a CNT solution near the receding contact line during tilted-drop casting and produced long-range nematic-like ordering of carbon nanotube stripes caused by confined micropatterned geometry. We further demonstrate that the performance of thin-film transistors based on these densely packed and uniformly oriented CNT arrays is largely improved compared to random CNTs. This approach has great potential in low-cost, large-scale processing of high-performance electronic devices based on high-density oriented CNT films with record electrical characteristics such as high conductance, low resistivity, and high career mobility.close878
Buckling instabilities in periodic composite polymeric materials
Although buckling instabilities in elastic solids have been known for a long time, high interest in this phenomenon is relatively recent. The current and prospective applications in flexible electronics, materials with tunable surface properties (adhesion and wettability), responsive photonic and phononic structures, and reinforced nanocomposites led to a surge in the interest in buckling instabilities. In fact, some of the applications, such as flexible electronics and metrology, have advanced at a tremendous pace only within the past few years. In this review, we discuss some of the most recent progress in the fundamental understanding of buckling instabilities in periodic multi-component polymer materials and porous polymer structures. We also discuss how the buckling can be localized to predetermined regions and hence form periodic instability patterns. Finally, we present several recent examples where buckling instabilities have been employed as a patterning tool to realize complex surface arrays of various materials
- …