Silver nanoparticles as antimicrobial agent: a case study on E. coli as a model for Gram-negative bacteria

5. In Situ Polymerization 3907 5.1. General Polymerization 3907 5.2. Photopolymerization 3910 5.3. Surface-Initiated Polymerization 3912 5.4. Other Methods 3913 6. Colloidal Nanocomposites 3913 6.1. Sol-Gel Process 3914 6.2. In Situ Polymerization 3916 6.2.1. Emulsion Polymerization 3917 6.2.2. Emulsifier-Free Emulsion Polymerization 3919 6.2.3. Miniemulsion Polymerization 3920 6.2.4. Dispersion Polymerization 3921 6.2.5. Other Polymerization Methods 3923 6.2.6. Conducting Nanocomposites 3924 6.3. Self Assembly 3926 7. Other Preparative Methods 3926 8. Characterization and Properties 3928 8.1. Chemical Structure 3928 8.2. Microstructure and Morphology 3929 8.3. Mechanical Properties 3933 8.3.1. Tensile, Impact, and Flexural Properties 3933 8.3.2. Hardness 3936 8.3.3. Fracture Toughness 3937 8.3.4. Friction and Wear Properties 3937 8.4. Thermal Properties 3938 8.5. Flame-Retardant Properties 3941 8.6. Optical Properties 3942 8.7. Gas Transport Properties 3943 8.8. Rheological Properties 3945 8.9. Electrical Properties 3945 8.10. Other Characterization Techniques 3946 9. Applications 3947 9.1. Coatings 3947 9.2. Proton Exchange Membranes 3948 9.3. Pervaporation Membranes 3948 9.4. Encapsulation of Organic Light-Emitting Devices 3948

Polymer/Silica Nanocomposites: Preparation, Characterization, Properties, and Applications

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New approaches to nanofabrication: molding, printing, and other techniques.

Recently, polymer nanocomposites reinforced with lower volume fraction of nanoceramics and carbon nanotubes have attracted steadily growing interest due to their peculiar and fascinating properties as well as their unique applications in commercial sectors. The incorporation of nanoceramics such as layered silicate clays, calcium carbonate or silica nanoparticles arranged on the nanometer scale with a high aspect ratio and/or an extremely large surface area into polymers improves their mechanical performances significantly. The properties of nanocomposites depend greatly on the chemistry of polymer matrices, nature of nanofillers, and the way in which they are prepared. The uniform dispersion of nanofillers in the polymer matrices is a general prerequisite for achieving desired mechanical and physical characteristics. In this review article, current development on the processing, structure, and mechanical properties of polymer nanocomposites reinforced with respective layered silicates, ceramic nanoparticles and carbon nanotubes will be addressed. Particular attention is paid on the structure–property relationship of such novel high-performance polymer nanocomposites.

Structural and mechanical properties of polymer nanocomposites

A literature review of modern transition-metal nanoclusters, with an emphasis on those nanoclusters which are catalytically active, is presented in two parts. Part One presents background information on transition-metal nanoclusters, including an overview of common synthetic routes, a description of how nanoclusters are stabilized, and a brief summary of the multiple characterization techniques used (and the type of information that they can provide). In Part Two, five specific nanocluster case studies are presented, case studies which compare and contrast the syntheses, characterization approaches, and catalytic applications of transition-metal nanoclusters.

A review of modern transition-metal nanoclusters: their synthesis, characterization, and applications in catalysis

Stable dispersions of nanosilica ranging in size between 8 and 11 nm were coated with tert-butyl acrylate polymer by in situ polymerization of monomer adsorbed on the particles in 2-propanol. The system was developed for use in the encapsulated inorganic resist technology. To achieve a high coating efficiency, silica was first modified with the 3-(trimethoxysilyl)propylmethacrylate (MPS) coupling agent at two different degrees of grafting. The presence of the bound MPS agent and of the polymer at the silica surface was determined by the attenuated total reflection infrared spectroscopy, while the amounts bound were assessed by the thermogravimetric analysis. Under studied conditions, the encapsulation efficiency was governed by the degree of MPS grafting and by the initial concentration of the monomer. Finally, the dissolution rate of these particles in aqueous base, a key parameter in photoresist application, was drastically reduced with increasing amount of grafted tert-butyl acrylate polymer at the sil...

Encapsulation of Nanosized Silica by in Situ Polymerization of tert-Butyl Acrylate Monomer†

The present invention is directed towards a fluid composition comprising a perfluoroehter compound; the fluid composition has an absorbance of less than about 2 cm-1 at a wavelength of about 157 nm. The present invention also comprises an optical system, a semiconductor device, and methods of modifying a silicon wafer, each employing the fluid composition comprising the perfluorether compound.

Optical fluids, and systems and methods of making and using the same

The requirements of liquids for use in immersion lithography are discussed. We present simple calculations of the transmission and index homogeneity requirements of the immersion liquid (T > 0.95 and δn < 5×10-7 respectively for sin θ = NA/n = 0.9 and a working distance of 1 mm) along with the temperature and pressure control requirements which follow from them. Water is the leading candidate immersion liquid for use at 193 nm, and we present data on its chemical compatibility with existing 193 nm resists through dissolution/swelling and surface energy studies. We find that it has a minimal impact on at least some current 193 nm resists. At 157 nm, suitably transparent immersion fluids remain to be identified. Perfluorinated polyethers (PFPE) are among the most transparent organics measured. The lowest PFPE absorbance at 157 nm can be further reduced by roughly a factor of two, from 6 to 3 cm-1 through removal of dis-solved oxygen. We also discuss our efforts to understand the origin of the remaining absorbance through supercritical CO2 fractionation.

Immersion liquids for lithography in the deep ultraviolet

The photodecomposition of vicinal dibromides at 266 nm produces bromine atoms with a quantum yield of ∼2.0. This results from an efficient primary photocleavage of a C-Br bond, followed by rapid elimination of a second bromine atom from radicalsofthe type RCH-CH 2 Br. This cleavage occurs with a lifetime of <20 ns at room temperature. Bromine atoms react with bromine ions with a rate constant of 1.6×10 10 M -1 s -1 to yield Br 2 .- , an easily detectable and long-lived radical ion. This reaction can be used as a probe in order to determine absolute rate constants for other reactions of bromine atoms

Laser flash photolysis determination of absolute rate constants for reactions of bromine atoms in solution

The photochemistry and photophysics of 2-methyl- (1), 2-(2‘-furylethylidene)- (2), and 2-[(4‘-methoxy)styryl]-4,6-bis(trichloromethyl)-1,3,5-triazine (3), three compounds that find application as photoacid generators in photoresist formulations, have been investigated under conditions of direct excitation and using various phenothiazine derivatives as photosensitizers. C−Cl bond cleavage is confirmed by laser flash photolysis as the primary photochemical step in the direct photolysis of these compounds; the chlorine atoms formed in this reaction can be detected by complexation with chloride anions or benzene. In the case of 1, this photodissociation occurs with a lifetime of <20 ns. The quantum yield of bond breaking for 1 after direct excitation as determined by laser flash photolysis and steady-state irradiations was found to be 30−40 times greater than for 2 and 3. The mechanism under sensitized conditions involves electron transfer from the excited phenothiazines to the triazines as the primary photoc...

Roger F. Sinta

Papers

Encapsulation of Nanosized Silica by in Situ Polymerization of tert-Butyl Acrylate Monomer†

Optical fluids, and systems and methods of making and using the same

Immersion liquids for lithography in the deep ultraviolet

Laser flash photolysis determination of absolute rate constants for reactions of bromine atoms in solution

Mechanistic Studies of Photoacid Generation from Substituted 4,6-Bis(trichloromethyl)-1,3,5-triazines