Formation of Colloidal Dispersions of Organic Materials in Aqueous Media by Solvent Shifting†

Langmuir ◽  
2003 ◽  
Vol 19 (16) ◽  
pp. 6367-6380 ◽  
Author(s):  
M. Christine Brick ◽  
Harvey J. Palmer ◽  
Thomas H. Whitesides
Keyword(s):  
Organic Materials ◽  
Aqueous Media ◽  
Colloidal Dispersions ◽  
Solvent Shifting

Aqueous Colloidal Dispersions of Polyaniline Particles

1989 ◽  
Vol 173 ◽  
Author(s):  
Steven P. Armes ◽  
Mahmoud Aldissi
Keyword(s):  
Aqueous Media ◽  
Colloidal Dispersions ◽  
Polymeric Surfactant ◽  
Poly Vinyl Alcohol ◽  
Rice Grain ◽  
Chemical Polymerization ◽  
Cast Films ◽  
Bulk Powder ◽  
Solution Cast ◽  
Aniline Polymerization

ABSTRACTColloidal polyaniline has been prepared in acidic aqueous media by a modified chemical polymerization of aniline in the presence of a tailor-made polymeric surfactant. The surfactant which acts as a steric stabilizer used in this study is derivatized poly(vinyl alcohol-co-vinyl acetate). This surfactant contains pendant aniline units which participate in the aniline polymerization, resulting in the formation of sterically-stabilized polyaniline particles which have a non-spherical “rice-grain” morphology.It is shown that this novel form of polyaniline is more processable than the bulk powder that is normally obtained from a conventional chemical synthesis. The solid-state conductivity of solution-cast films or compressed pellets of these dispersions is surprisingly high (⋍ 1 S/cm), despite the presence of the insulating outer layer of chemically-grafted stabilizer.

scholarly journals Multicomponent bionanocomposites based on clay-nanoarchitectures for electrochemical devices

2019 ◽  
Author(s):  
Giulia Lo Dico ◽  
Bernd Wicklein ◽  
Lorenzo Lisuzzo ◽  
Giuseppe Lazzara ◽  
Pilar Aranda ◽  
...  
Keyword(s):  
Individual Component ◽  
Critical Role ◽  
Aqueous Media ◽  
Halloysite Nanotubes ◽  
Colloidal Dispersions ◽  
Biofuel Cells ◽  
Membrane Properties ◽  
Enzymatic Biofuel Cells ◽  
Electrochemical Devices ◽  
Selection Of

Based on the unique ability of defibrillated sepiolite (SEP) to form stable and homogeneous colloidal dispersions of diverse types of nanoparticles in aqueous media under ultrasonication, multicomponent conductive nanoarchitectured materials integrating halloysite nanotubes (HNT), graphene nanoplatelets (GNP) and chitosan (CHI) have been developed. The resulting nanohybrid suspensions could be easily conformed either as films or as foams, where each individual component plays a critical role in the biocomposite: HNT acts as nanocontainer for bioactive species, GNP provide electrical conductivity (enhanced by doping with MWCNT) and, the CHI polymer matrix introduces mechanical and membrane properties, which are of key significance for the development of electrochemical devices. The resulting characteristics open the way to use these active elements as integrated multicomponent materials for advanced electrochemical devices such as biosensors and enzymatic biofuel cells. This strategy can be regarded as an “a la carte menu”, where the selection of the nanocomponents provided with diverse properties will determine a functional set of predetermined utility thanks to the SEP behavior to maintain stable colloidal dispersions of different nanoparticles and polymers in water.

scholarly journals Multicomponent bionanocomposites based on clay nanoarchitectures for electrochemical devices

2019 ◽  
Vol 10 ◽  
pp. 1303-1315 ◽  
Author(s):  
Giulia Lo Dico ◽  
Bernd Wicklein ◽  
Lorenzo Lisuzzo ◽  
Giuseppe Lazzara ◽  
Pilar Aranda ◽  
...  
Keyword(s):  
Individual Component ◽  
Critical Role ◽  
Aqueous Media ◽  
Halloysite Nanotubes ◽  
Colloidal Dispersions ◽  
Biofuel Cells ◽  
Membrane Properties ◽  
Enzymatic Biofuel Cells ◽  
Electrochemical Devices ◽  
Selection Of

Based on the unique ability of defibrillated sepiolite (SEP) to form stable and homogeneous colloidal dispersions of diverse types of nanoparticles in aqueous media under ultrasonication, multicomponent conductive nanoarchitectured materials integrating halloysite nanotubes (HNTs), graphene nanoplatelets (GNPs) and chitosan (CHI) have been developed. The resulting nanohybrid suspensions could be easily formed into films or foams, where each individual component plays a critical role in the biocomposite: HNTs act as nanocontainers for bioactive species, GNPs provide electrical conductivity (enhanced by doping with MWCNTs) and, the CHI polymer matrix introduces mechanical and membrane properties that are of key significance for the development of electrochemical devices. The resulting characteristics allow for a possible application of these active elements as integrated multicomponent materials for advanced electrochemical devices such as biosensors and enzymatic biofuel cells. This strategy can be regarded as an “a la carte” menu, where the selection of the nanocomponents exhibiting different properties will determine a functional set of predetermined utility with SEP maintaining stable colloidal dispersions of different nanoparticles and polymers in water.

Polymeric and Organic Electronic Materials: From Scientific Curiosity to Applications

MRS Bulletin ◽  
1997 ◽  
Vol 22 (6) ◽  
pp. 13-15 ◽  
Author(s):  
Arthur J. Epstein ◽  
Yang Yang
Keyword(s):  
Organic Materials ◽  
Energy Gap ◽  
Electronic Materials ◽  
Aqueous Media ◽  
Semiconducting Polymers ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
The Past ◽  
Scientific Curiosity ◽  
Doped Polymers

While polymers and organic materials have been known and utilized broadly for many decades, finding such materials with the intrinsic properties of semiconductors and metals is a relatively recent phenomenon. The report in 1977 about doping polyacetylene to achieve relatively high conductivity opened up important new vistas for chemistry and physics, and for technology in general. This report recognized that a key feature of the electronic polymers and organic materials was a backbone consisting of alternating single and double bonds resulting in a “π-conjugated network.” This in turn led to a relatively small energy gap, enabling the appearance of both semiconducting and metallic properties.Initially these polymers were unstable in air and not readily processed. Over the past decade, major advances have occurred in the synthesis of new forms of conducting and semiconducting polymers that enable processing under a broad range of conditions including organic solvents, inorganic solvents, and aqueous media. There are even meltprocessable versions of some of the electronic polymers.A prime focus of the field has been the determination of the mechanisms for charge conduction and the intrinsic conductivity of these fascinating materials, especially doped polymers. In the past decade, interest has increased in the semiconducting (generally undoped) forms of these polymers and organic materials, including their photophysics and their use in a wide variety of devices. The reports of light-emitting devices fabricated from molecular and oligomeric constituents in the mid-1980s and from polymeric constituents in 1990 stimulated interest in this area of research.

Triplet State Processes in Aqueous Colloidal Dispersions of Polycyclic Aromatic Hydrocarbons at Room Temperature

1985 ◽  
Vol 39 (3) ◽  
pp. 516-519 ◽  
Author(s):  
Robert Weinberger ◽  
L. J. Cline Love
Keyword(s):  
Room Temperature ◽  
Aqueous Media ◽  
Colloidal Dispersions ◽  
Delayed Fluorescence ◽  
Room Temperature Phosphorescence ◽  
Aromatic Molecules ◽  
Dissolved Matter ◽  
Polycyclic Aromatic ◽  
Insoluble Compounds

A unique and facile means of producing room-temperature phosphorescence (RTP) from colloidal or microcrystalline suspensions of aromatic molecules in aqueous media is reported. Unlike previously reported RTP techniques, colloidal RTP is insensitive to quenching by dissolved oxygen. Delayed fluorescence was observed from several non-phosphorescent species. Potential uses of the technique are for the determination of the solubility of highly insoluble compounds and the ability to distinguish between suspended and dissolved matter.

Application of Improved Voltage Compensation in the SEM to Imaging of Organic Materials

1973 ◽  
Vol 31 ◽  
pp. 444-445
Author(s):  
P.J. Killingworth ◽  
M. Warren
Keyword(s):  
Electron Beam ◽  
Organic Materials ◽  
Operating Parameters ◽  
Low Density ◽  
Beam Diameter ◽  
Incident Electron Beam ◽  
Specimen Material ◽  
Voltage Compensation ◽  
Selection Of ◽  
Scanning Electron

Ultimate resolution in the scanning electron microscope is determined not only by the diameter of the incident electron beam, but by interaction of that beam with the specimen material. Generally, while minimum beam diameter diminishes with increasing voltage, due to the reduced effect of aberration component and magnetic interference, the excited volume within the sample increases with electron energy. Thus, for any given material and imaging signal, there is an optimum volt age to achieve best resolution.In the case of organic materials, which are in general of low density and electric ally non-conducting; and may in addition be susceptible to radiation and heat damage, the selection of correct operating parameters is extremely critical and is achiev ed by interative adjustment.

200kv superconducting cryo electron microscope

1987 ◽  
Vol 45 ◽  
pp. 642-643
Author(s):  
M. Iwatsuki ◽  
Y. Kokubo ◽  
Y. Harada ◽  
J. Lehman
Keyword(s):  
Electron Microscope ◽  
Structure Analysis ◽  
Organic Materials ◽  
Strong Interactions ◽  
Specimen Preparation ◽  
Great Effort ◽  
Electron Microscopic ◽  
Crystal Fields ◽  
Special Skill ◽  
Long Time

In recent years, the electron microscope has been significantly improved in resolution and we can obtain routinely atomic-level high resolution images without any special skill. With this improvement, the structure analysis of organic materials has become one of the interesting targets in the biological and polymer crystal fields.Up to now, X-ray structure analysis has been mainly used for such materials. With this method, however, great effort and a long time are required for specimen preparation because of the need for larger crystals. This method can analyze average crystal structure but is insufficient for interpreting it on the atomic or molecular level. The electron microscopic method for organic materials has not only the advantage of specimen preparation but also the capability of providing various information from extremely small specimen regions, using strong interactions between electrons and the substance. On the other hand, however, this strong interaction has a big disadvantage in high radiation damage.

STM of freeze-fracture replicas: Problems and promises

1993 ◽  
Vol 51 ◽  
pp. 68-69
Author(s):  
J. T. Woodward ◽  
J. A. N. Zasadzinski
Keyword(s):  
Scanning Tunneling Microscope ◽  
Organic Materials ◽  
Freeze Fracture ◽  
Atomic Resolution ◽  
Scanning Tunneling ◽  
Tunneling Microscope ◽  
Molecular Scale ◽  
Organic Surfaces ◽  
Metal Layers ◽  
Conductive Surfaces

The Scanning Tunneling Microscope (STM) offers exciting new ways of imaging surfaces of biological or organic materials with resolution to the sub-molecular scale. Rigid, conductive surfaces can readily be imaged with the STM with atomic resolution. Unfortunately, organic surfaces are neither sufficiently conductive or rigid enough to be examined directly with the STM. At present, nonconductive surfaces can be examined in two ways: 1) Using the AFM, which measures the deflection of a weak spring as it is dragged across the surface, or 2) coating or replicating non-conductive surfaces with metal layers so as to make them conductive, then imaging with the STM. However, we have found that the conventional freeze-fracture technique, while extremely useful for imaging bulk organic materials with STM, must be modified considerably for optimal use in the STM.

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