This book provides a multidisciplinary introduction to the subject of Langmuir–Blodgett films. These films are the focus of intense current worldwide interest, as the ability to deposit organic films of nanometre thicknesses has many implications in materials science, and in the development of new electronic and opto-electronic devices. Beginning with the application of simple thermodynamics to the common bulk phases of matter, the book outlines the nature of the phases associated with floating monolayer films. The Langmuir–Blodgett deposition process itself is described in some detail and contrasted with other thin film techniques. Monolayer-forming materials and the structural, electrical and optical properties of Langmuir–Blodgett films are discussed separately. Each chapter is comprehensive, easy to understand and generously illustrated. Appendices are provided for the reader wishing to delve deeper into the physics and chemistry background.
The Langmuir−Blodgett deposition of organically passivated gold nanoparticles is reported. A monolayer of these particles has been incorporated into a metal−insulator−semiconductor (MIS) structure. The MIS device exhibits a hysteresis in its capacitance versus voltage characteristic, the magnitude of which is dependent on the voltage sweep conditions. Charge storage in the layer of nanoparticles is thought to be responsible for this effect.
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The robust advances in pain management for companion animals underlie the decision of AAHA and AAFP to expand on the information provided in the 2007 AAHA/AAFP Pain Management Guidelines for Dogs and Cats . The 2015 guidelines summarize and offer a discriminating review of much of this new knowledge. Pain management is central to veterinary practice, alleviating pain, improving patient outcomes, and enhancing both quality of life and the veterinarian-client-patient relationship. The management of pain requires a continuum of care that includes anticipation, early intervention, and evaluation of response on an individual-patient basis. The guidelines include both pharmacologic and nonpharmacologic modalities to manage pain; they are evidence-based insofar as possible and otherwise represent a consensus of expert opinion. Behavioral changes are currently the principal indicator of pain and its course of improvement or progression, and the basis for recently validated pain scores. A team-oriented approach, including the owner, is essential for maximizing the recognition, prevention, and treatment of pain in animals. Postsurgical pain is eminently predictable but a strong body of evidence exists supporting strategies to mitigate adaptive as well as maladaptive forms. Degenerative joint disease is one of the most significant and under-diagnosed diseases of cats and dogs. Degenerative joint disease is ubiquitous, found in pets of all ages, and inevitably progresses over time; evidence-based strategies for management are established in dogs, and emerging in cats. These guidelines support veterinarians in incorporating pain management into practice, improving patient care.
We report on the solubilization, phase behavior, and self-organized colloidal structure of a ternary waterpolyfluorene-surfactant (amphiphile) system comprised of polyelectrolytic poly{1,4-phenylene[9,9-bis(4-phenoxybutylsulfonate)]fluorene-2,7-diyl} (PBS-PFP) in nonionic pentaethylene glycol monododecyl ether (C 12 E 5 ) at 20°C. We show in particular how a high amount (milligrams per milliliter) of polyfluorene can be solubilized by aqueous C 12 E 5 via aggregate formation. The PBS-PFP and C 12 E 5 concentrations of 0.31 × 10 -4 -5 × 10 -4 M and 2.5 × 10 -4 -75 × 10 -4 M, respectively, were used. Under the studied conditions, the photoluminescence (PL), surface tension, static contact angle, and (π-A) isotherm measurements imply that D 2 O-PBS-PFP(C 12 E 5 ) x realizes three phase regimes with an increasing molar ratio of surfactant over monomer unit (x). First, for x e 0.5, the mixture is cloudy. In this regime polymer is only partially dissolved. Second, for 1 e x e 2, the solution is homogeneous. In this regime polymer is dissolved down to the colloidal level. Small-angle neutron scattering (SANS) patterns indicate rigid elongated (polymer-surfactant) aggregates with a diameter of 30 Å and mean length of ∼900 Å. The ratio between contour length and persistence length is less than 3. Third, for x g 4, the solution is homogeneous and there is cooperative binding between polymer and surfactant. Surface tension, contact angle, and surface pressure remain essentially constant with increasing x. A PL spectrum characteristic of single separated polyfluorene molecules is observed. SANS curves show an interference maximum at q ∼ 0.015 Å -1 , indicating an ordered phase. This ordering is suggested to be due to the electrostatic repulsion between polymer molecules adsorbed on or incorporated into the C 12 E 5 aggregates (micelles). On dilution the distance between micelles increases via 3-dimensional packing. In this regime the polymer is potentially dissolved down to the molecular level. We show further that the aggregates (x ) 2) form a floating layer at the air-water interface and can be transferred onto hydrophilic substrates.
In this paper, we focus on the synthesis and structure of the new bis(1,3,4-oxadiazole) system 2,5-bis[2-(4-tert-butylphenyl)-1,3,4-oxadiazol-5-yl]pyridine (PDPyDP). We have fabricated light-emitting diodes (LEDs) using poly[2-methoxy-5-(2-ethylhexoxy)-1,4-phenylene vinylene] (MEH-PPV) as the emissive material, with and without a thermally evaporated electron-injection/hole-blocking layer of either PDPyDP or its vinylene analogue (E)-1,2-bis-[2-(4-tert-butylphenyl)-1,3,4-oxadiazol-5-yl]ethene (PDVDP) or its phenylene analogue 1,4-bis[2-(4-tert-butylphenyl)-1,3,4-oxadiazol-5-yl]benzene (PDPDP). PDPDP is the para isomer of OXD-7, which is a widely used molecular electron-transporting material. Electroluminescence spectra indicate that light is emitted only from the MEH-PPV layer. Using aluminum as the cathode, the bilayer LED with PDPyDP is considerably more efficient than the corresponding single-layer device or devices with PDVDP or PDPDP as the electroninjection layer.
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