查看完整版本: 静电自组装,Electrostatic Self-Assembly

nanosurface 2006-12-09 02:39

静电自组装,Electrostatic Self-Assembly

[quote]静电自组装( Elect rostatic Self2Assembly Multilayer ,ESAM) 法是一种制膜技术，ESAM 法通过带相反电荷的聚离子或荷电微小粒子交替沉积,依靠静电引力吸附成膜,不需要形成化学键,具有在分子水平控制膜的组成和结构的特性,厚度和应力分布均匀,热稳定和长期稳定性较好.近年来已有人利用ESAM 法制备了发光器件、导电膜、非线性光学器件等,显示出这种技术在光、电、磁等学科领域有广阔的应用前景[/quote]T7r3Ts,O*F
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NanoSonic has exclusively licensed nine patents covering electrostatic self-assembly (ESA) processing and use from Virginia Tech Intellectual Properties (VTIP), Inc., and has separately developed its own intellectual property to enable process, material, and device commercialization. ESA allows the ultra-uniform formation of multiple, nanometer-thick layers of material into functional thin films, and recent modifications allow the formation of thicker films and bulk materials.
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\*{$q)y_#pg3p3As Our company has created a "library" of self-assembled materials, many of them based on ESA processing, and has demonstrated the synthesis of more than 2000 individual material layers. We have also developed measurement capabilities to rapidly evaluate materials and new modifications to the self-assembly processes.
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1{ y;iPI(Y+k ESA processing involves the simple dipping of a chosen substrate into alternate aqueous solutions containing anionic and cationic materials such as: complexes of polymers; metal and oxide nanoclusters; cage-structured molecules such as fullerenes; and proteins and other biomolecules. Design of these individual precursor molecules, and control of the order of the multiple molecular layers through the thickness of the film, allow control over macroscopic electrical, optical, magnetic, thermal, mechanical, and other properties, important to many engineering devices and applications.
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The nearly perfect molecular order of the individual monolayers is the net result of many individual molecules seeking local least energy configurations when adsorbed from water solutions to bond with molecules already attached at the substrate surface. The interpenetration of molecules in adjacent layers may be controlled to benefit macroscopic material and device characteristics.
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[url]http://arxiv.org/pdf/cond-mat/0501083[/url]2OtqK#\'`N"{

H.gMS(P K)U hQ [[i] 本帖最后由 nanosurface 于 2006-12-09 02:43 编辑 [/i]]

nanosurface 2006-12-09 02:45

Electrostatic Self-Assembly of Nanoparticles

[b]Summary: [/b]    NanoSonic, Inc., is refining a molecular self-assembly process, calledelectrostatic self-assembly (ESA), that produces thin films withmaterial properties that can be precisely controlled. The synthesis canbe performed at room temperature, is environmentally benign, and can bedone on a variety of substrate materials. ESA could be used to producematerials with superior electrical, mechanical, and opticalconstitutive properties. NanoSonic is currently developing novelmaterials and associated devices.
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        [b]Technology Description: [/b]B0w-W"n+un!n9c
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NanoSonic, Inc., (Blacksburg, VA) is refining a molecularself-assembly process, called electrostatic self-assembly (ESA), thatcan produce thin film materials with nanoscale-level molecularuniformity: as such, it is an enabling technology for producing thinfilms with precise control of their physical properties. In comparisonto conventional manufacturing methods, ESA processing offers a numberof advantages. ESA is a simple, low-cost fabrication method that isperformed at room temperature and is environmentally benign. Itrequires little capital investment, since little specialized equipmentis required, and offers many technical advantages such as 1) thecapability to deposit on almost any substrate, including plastics andirregularly-shaped or very large substrates, which pose a problem foralternate techniques, 2) the capability to precisely grade optical,electrical, mechanical, thermal, and other properties on the nanometerscale, and 3) the potential to easily pattern the resulting films.{0g'x@,|u]h:H

[a-y g D)a In ESA synthesis, a substrate is simply dipped into alternate aqueoussolutions containing anionic and cationic materials such as polymercomplexes; metal and oxide nanoclusters; cage-structured molecules suchas fullerenes; and proteins and other biomolecules. Nearly perfectmolecular order is achieved by individual molecules seeking leastenergy configurations (the tendency of any substance to change to thestate of least energy). Adsorbed from water solutions, these moleculesbond with others already attached at the substrate surface. Materialproperties can then be precisely controlled through the successivestacking of ultra-uniform, nanometer-thick layers of the film.
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Other advantages of the ESA process include: DQE~ c
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•Fast thin-film formation: The ESA molecular adsorption process shouldonly require seconds for molecules to form least energy configurationalbonds at the substrate surface, making practical the rapid formation ofrobust multilayer systems.
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•Large surface-area application: Using simple dipping or spraying,alternating ionic bonding allows the fabrication of multilayer thinfilms over very large surfaces of structural materials.'J^%Y u'b

{*s!Eot$k._B.b •Thin-film synthesis at room temperature and pressure: Avoidance ofhigh-temperature burnout processing means that multilayer coatings canbe created on any solid substrate or active device material, includingpolymer composite structural members and separation membrane materialswithout material degradation. Flexible electronic material designallows a wide variety of organic and inorganic materials to be used;this additionally allows tailoring of the electronic work function,thus improving the external quantum efficiency of electronic andelectro-optic devices.
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#O0wU-Z/]\Yup •Compatibility with conventional low-cost photolithographic processes:Multiple ESA material layers self-assembled by ionic bonding may bepatterned using charge stamping, photolithography, nanoimprintlithography, UV laser irradiation, and other methods to createlarge-scale integrated devices. ESA is an environmentally friendlyprocess, involving no volatile organic compounds and consumingnegligible electricity."L#a#l&E~,D zYwn U

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    [b]BMD Origins: [/b]2q};[-T GI6x)}
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Through BMDO STTR and SBIR contracts, NanoSonic demonstratedthe feasibility of using ESA to develop a variety of materials. Oneclass of material demonstrated was nonlinear optical (NLO) thin films.NLO thin films can replace telecommunications mechanical components,improving speed and reliability. Additional BMDO SBIR work wasundertaken to demonstrate the feasibility of using ESA processes tointegrate such multiple functions as electromechanical actuation,semiconductor junction-based signal processing, thermal transport,optical switching and modulation into nanostructured organic/inorganicthin-film actuator materials. These materials could be useful inspacecraft control. ESA has also received SBIR development funding fromDARPA, the Air Force, NASA, the National Science Foundation, and NIST.
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    [b]Spinoff Applications: [/b]
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The potential commercial product applications ofself-assembled nanomaterials, and devices that may be formed using suchmaterials, is widespread for several reasons. Fundamentally, thenanometer-scale dimension of the molecules used to form such materialsleads to important variations in energy band properties. Thesevariations result in the modification and improvement of macroscopicengineering properties in these nanomaterials as opposed to those foundin conventional bulk materials. The improvements are in suchcharacteristics as electrical conductivity, magnetic permeability, andmechanical hardness.
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q0]I wJx%l Self-assembled nanomaterials have numerous product applications. Forinstance, ESA could be used to produce materials with superiorelectrical properties, such as conformal electrodes on ultrasmallelectronic devices and electrically conducting surface coatings onceramic, polymer, and other substrates. NanoSonic has demonstrated theability to form metal nanocluster/polymer composite films as thin asseveral tens of nanometers. The electrical conductivity of these filmsis in excess of that of conducting polymers and conventionalopto-electronic electrode materials such as indium tin oxide (ITO).Another possible application would be for specially tailoredpolymer/polymer and nanocluster/polymer nanocomposites that can displaypiezoelectric behavior. These would include such products as ultrasmallactuation or sensing elements for microelectromechanical devices,biological probes and manipulators, and conformal large-area actuators.
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A third possible market may be for nonlinear optical (NLO) films.NanoSonic found that the ESA processing method yieldsnoncentrosymmetric molecular structures that possess a remarkably largesecond-order NLO response, without the need for electric field polingthat other methods require. This second-order response allows nonlinearoptics to alter the frequency, signal strength, or othercharacteristics of light through an electrical control signal, whichmeans they can replace bulkier mechanical components such as beamsplitters and switches.
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Qh;x @n!rs     [b]Commercialization: [/b]
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5sh e m*If NanoSonic is developing novel materials and associated devicesbased on ESA. Current products include a range of precursor materialsand aqueous solutions suitable for ESA-based material synthesis, acustom robotic system for ESA manufacturing, and prototype functionalmaterials for laboratory analysis. Within 2-5 years, the company willstart selling selected thin films and eventually sell a full line offilms and machines, while also licensing out its processes to othercompanies.bk w'^#v-i+k-[i"`

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    [b]Company Profile: [/b]
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iX5~HY4Sb n!JJ NanoSonic Inc. is a Blacksburg, Virginia based company,created in 1998 in cooperation with Virginia Polytechnic Institute andState University, and with the State of Virginia. The company employs11 people. u^&U,w t2SK@ Y#t
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NanoSonic exclusively licensed nine ESA-related patents from VirginiaTech (from Virginia Tech Intellectual Properties, Inc.), where it wasfirst developed. It has also separately developed its own intellectualproperty to enable process, material, and device commercialization. Thecompany has created a ''library'' of self-assembled materials and hasdemonstrated the synthesis of more than 2,000 individual materiallayers.4UHnA Q0] @3r
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NanoSonic maintains 7,000 square feet of newly renovated laboratory andoffice space. Facilities include equipment for the design and synthesisof material precursors, the formation of synthesized precursors intothin- and thick-film materials, the engineering of materials intodevices, and the manufacture of multiple elements.
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m W1Xy;x^d     [b]Contact Information: [/b]Richard O. Claus, Ph.D. (president)
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E-mail:  info@nanosonic.com
h+XPF)T Web Site:  www.nanosonic.com

nanosurface 2006-12-09 02:49

[b][size=3][color=Red]Electrostatic Self-Assembly[/color][/size][/b] :pdf :fulltext
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@Z5J)|/A6T!k2x*~0~ [url=http://scholar.lib.vt.edu/theses/available/etd-06152000-22000010/unrestricted/etd.PDF][b][color=Blue]Linear Optical Thin Films Formed by Electrostatic Self-Assembly[/color][/b][/url]
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0E~lr)I&P9s1g_ [url=http://www.mpip-mainz.mpg.de/documents/forschungsprojekte/c7.pdf]Electrostatic Self-Assembly[/url]

nanosurface 2006-12-09 02:54

Learn Electrostatic Self-Assembly

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j|W lX0jS%} Scientists are just beginning to take advantage of self-assembly to make new things at the molecular scale. This is part of nanotechnolgy, a new field that may one day lead to the invention of tiny molecular machines that do incredible things like patrol your bloodstream destroying viruses, or clean up pollutants molecule by molecule.  One useful thing people can already make with self-assembly is a monolayer. A monolayer is a sheet exactly one molecule thick. Materials behave differently in monolayers, so they can have many interesting properties, like increased conductivity and flexibility.  The model below shows some yellow molecules that assemble into a monolayer on the green surface. Run the model, then use the buttons to charge the green atoms.9H"S$\z2t`M/sW
Please try yourself!T&dvrPD
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[url=http://molo.concord.org/database/activities/157.html]http://molo.concord.org/database/activities/157.html[/url]
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