Detecting gamma-ray emission from radionuclides hidden within containers is a significant concern to national security and can be accomplished with scintillating materials such as NaI:Tl, LaBr3:Ce crystals. However, the use of these high quality crystals limits the functionality of the detectors due to their high cost and scalability issues. Therefore the development of more durable, more easily manufactured, and more cost effective scintillating materials is desired. The incorporation of nanophosphors or Quantum Dots (QDs) into a polymer matrix to produce a transparent nanocomposite could potentially provide an alternative method to fabricate scintillating detectors. Embedded in a suitable polymer matrix, nanocomposite detectors may be easily made suitably large for portal monitors. Also, preparation of suitable particle sizes and/or compositions permits selection of a photon wavelength that optimally matches the photodetector response curve to increase the number of photons collected per pulse. In this paper a series of LaF3:Ce nanophosphors with varying doping concentrations (1–30mol%Ce) were synthesized using a chemical precipitation method. Photoluminescence and photoluminescence excitation characterizations indicated that the highest luminescent intensity was obtained from the 20%Ce doped sample with a peak emission at 325 nm. The refractive indices of the nanoparticles were identified by index matching measurements. Then an index matched epoxy was selected for incorporation of these nanoparticles to prepare transparent nanocomposite scintillators. In addition, colloidal solutions of CdTe QDs with various emitting colors were synthesized and incorporated into a Polymethyl-methacrylate (PMMA) matrix to make transparent nanocomposites. An initial evaluation of the scintillation behavior of these nanocomposites was evaluated by exposure to gamma rays.

Nanocomposites are of increasing interest due to their unique structural, electronic, and thermal properties. Simultaneously, multiscale molecular modeling is becoming more robust. Therefore computational models are able to be examined with increased accuracy, complexity, and dimension. Graphene based molecules are lauded for their conductive properties as well as their architecture-like geometry which may allow bottom up nanoscale fabrication of nanoscopic structures. Furthermore, these macrocycled molecules allow high interactivity with other molecules including highly tensiled polymers that yield other novel supramolecular structures when interacted. These supramolecular structures are being investigated in lieu of a variety of potential applications. Nanocomposites of cured epoxy resin reinforced by single-walled carbon nanotubes exhibit a plethora of interesting behavior at the molecular level. A fundamental issue is how the self-organized dynamic structure of functional molecular systems affects the interactions of the nano-reinforced composites. A combination of force-field based molecular dynamics and local density-functional calculations shows that the stacking between the aromatic macrocycle and the surface of the SWNTs manifests itself via increased interfacial binding. First-principles calculations on the electronic structures further reveal that there exists distinct level hybridization behavior for metallic and semiconducting nanotubes. In addition there is a monatomic increase in binding energy with an increase in the nanotube diameter. The simulation studies suggest that graphene nanoplatelets are potentially the best fillers of epoxy matrices. The implications of these results for understanding dispersion mechanism and future nanocomposite developments are discussed.

Model polymer nanocomposites based on geometrically well defined and protected Laponite particles dispersed in Poly(ethylene oxide) were investigated in order to improve the understanding of the filler dispersion effects on rheology by varying two experimental factors, namely preparation method and PEO matrix molecular weight. Preparation methods are divided into a solution dispersion and a melt dispersion by twin screw extrusion. The linear viscoelastic properties of the samples prepared by solution method revealed an elastic solid like behaviour at Laponite weight fractions as low as 0.1%, dramatically lower than the percolation threshold so far reported for such kind of systems. The sample preparation by melt dispersion, although leading to dispersed particles, does not achieve the same levels of modulus as compared to solution prepared mixtures. We propose a qualitative interpretation of this phenomenon, based on the mixture between a liquid and a dispersed phase of rather solid character. Further experiments using small angle X-ray scattering techniques (SAXS) show that the modulus level is not necessarily related to the height of the correlation peak characteristic of the Laponite stacks. However, for samples prepared with varying PEO matrix molecular weight the fraction of Laponite stacks decreases with increasing PEO molecular weight. The rheology master curve analyses show that confinements of polymer chains arising from high concentrations of particles and high molecular weight matrix chains do not impact the level of the low frequency modulus. However, a slower polymer dynamics, as observed for higher molecular weights, leads to an increase of the modulus at low particle loadings.

The conventional dye sensitized solar cell (DSSC) is limited by the use of a liquid electrolyte that is prone to leakage and evaporation. Efforts to replace the liquid with a solid equivalent have been met with difficulties in penetrating the mesoporous TiO2 nanostructured photoanode with liquid processing, particularly for photoanode layer thickness greater than 2 μm. Here, initiated chemical vapor deposition (iCVD) is successfully applied to directly synthesize and fill the pores of the mesoporous TiO2 network of up to 12 μm thickness with poly(2-hydroxyethyl methacrylate) (PHEMA) polymer electrolyte. Comparing with equivalent liquid electrolyte cells, DSSCs integrated with PHEMA polymer electrolyte showed consistently higher open circuit voltage, which is attributed to a decrease in electron recombination with the redox couple at the electrode-electrolyte interface.

To explore competitive or cooperative effects novel organic-inorganic hybrid copolymers are being prepared and studied. The use of polyhedral oligomeric silsesquioxanes (POSS), a molecularly precise isotropic comonomer, is being utilized to take advantage of the inherent size scale of these particles, average diameters of 1-2 nm. The organic component selected for study in these hybrid systems are either semi-crystalline or amorphous polymers. The architectures of the hybrid copolymers range from random, to precise block copolymers, as well as telechelic and hemi-telechelic end-functionalized model compounds. The degree of POSS aggregation that occurs is found to be a function of thermal history, and processing conditions. Templating, or arresting, aggregation can be achieved using either crystalline organic polymer scaffolds in the bulk. The second inorganic comonomers for study has been constructed from icosahedral carboranes. Dicarbo-closo-decaboranes have been widely investigated for their thermal stability, chemical resistance, unique geometry, and the high cross-section for the capture of thermal neutrons. While carboranes have been widely incorporated into small molecules, metal complexes, and on a limited basis in polymer systems relatively little work exists relating their unique properties to systems with extended π-conjugation. Details of the syntheses, characterization and performance properties of both sets of hybrid systems will be discussed.

A polypyrrole (PPy) nanocellulose composite was shown to cycle well over 3000 cycles in 2.0 M NaCl electrolyte when used as the active material for both electrodes in an energy storage device. SEM micrographs show a highly porous nature of the conductive paper material and electrochemical charge-discharge measurements, as well as external electrode potential monitoring, confirm the good cycling behavior of the material.

Polyaniline nanofibres (PAni) can be surface modified to improve electroactivity over a broader pH range. The technique we describe here can be used to attach carboxylic acid terminated substituents. Modified nanofibres maintain their high surface area, and ability to switch between different redox states. These properties make the material suitable for sensing applications. Unlike unmodified PAni, the functionalised material is self-doping and hence more stable in higher pH solutions. Here we demonstrate how modified PAni fibres can be used for the detection of ascorbic acid.

Polydimethylsiloxane (PDMS) is one of the most used materials in bio-applications. However, previous works were mainly focus on the mechanical aspect. In this paper we presented a practical and efficient approach to enhance the electrical properties of PDMS by using conducting polymer nanowires (CPNWs). The nanowires were synthesized using template method and added in PDMS to form nanocomposites. The dielectric constants of the composites were characterized by impedance measurements, and the dielectric relaxation behavior and the volume fraction of CPNWs was investigated. Based on the percolation theory a much lower threshold (5.3 vol%) was achieved.

Surface modification of jute fibers was accomplished by performing chemical treatments including detergent washing, dewaxing, alkali, and acetic acid treatment. Morphology of modified surfaces examined using scanning electron microscopy (SEM) revealed improved surfaces for better adhesion with matrix. Better thermal performance of treated fibers was found from thermogravimetric analysis (TGA). Enhanced tensile properties of treated fibers were obtained from tensile tests. Using solution intercalation technique and magnetic stirring, 2%, 3%, and 4% by weight Montmorillonite K10 nanoclay were dispersed into a biodegradable polymer, Biopol. Thermal performance of nanoclay infused Biopol characterized using dynamic scanning calorimetry (DSC) showed improved degree of crystallinity by 7%. Jute fiber reinforced Biopol biocomposites with and without nanoclay were manufactured using treated and untreated jute fibers by compression molding process. Thermal and mechanical responses of treated fiber reinforced Biopol composites (TJBC) without nanoclay evaluated using dynamic mechanical analysis (DMA) and flexure tests showed 9% and 12% increase in storage modulus and flexure strength, respectively, compared to untreated jute fiber reinforced composites (UTJBC). The respective values were 100% and 35% for 4% nanoclay infused TJBC compared to UTJBC without nanoclay.

The fluorocarbon/SiO2 hybrid sol (L) for low refractive index coating was made by tetraethoxysilane (TEOS) and polytetrafluoroethylether derivative(PTFEED) with the hydrolysis and condensation in ethanol to get with coating refractive index as (nL=1.38). It can be coated on glass with single layer by quarter wave, the anti-reflective (AR) coating glass would have less than 3 % reflection. The TiO2 hybrid sol are prepared by tetraisopropyl orthotitanate(TPOT) with silane coupling agent and acrylic resin. The TiO2 hybrid sol with the coating refractive index (nH=1.75) used as high refraction coating sol (H). More acrylic resin added to get less coating refractive index (nM=1.65) used as middle refractive coating sol (M). Three layers AR coating glass can be made by M/H/L design to get 1.0 % reflection, have 3H hardness, 500g scratch resistance, and 107° water contact angle. These two kinds AR coating with fluorocarbon /SiO2 hybrid sol (L) coating on surface has anti-stain efficacy, which can be applied on the touch panel screen of flat panel display for mobile phone, PDA and e-book.

The effect of processing (shear) time on the mechanical behavior and thermal stability of multiwalled nanotube reinforced polyethylene was investigated. It was observed that the mechanical property (storage modulus, loss modulus) of the composites is process dependant whereas the thermal stability does not. The increase in mechanical behavior is attributed to a stronger interface between the nanotube and the polymer matrix.

The effect of pH was investigated on the morphological and spectroscopic properties of PANI thin films on PET. PANI/PET strips were prepared by a pattern-printing technique and coated with a thin film of polyaniline in situ emeraldine oxidation state, doped with HCl (PANI-HCl), obtained by in situ polymerization. AFM, UV-VIS-NIR and FTIR/ATR spectroscopic results showed that pH has a great influence on the polymer layer morphology of the coating layers, while the intensity of vibrational bands decreases with rising pH, increase due to changes in the H-bonded structure in the polymer chain.

A soluble polyaniline was synthesized through emulsion polymerization and characterized using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), gel permeation chromatography (GPC), viscosity analysis, and coefficient of linear thermal expansion (CLTE) determination. The electrical conductivity is found to reach 1000 S/cm with specific post doping treatments. Multiple printing processes, such as inkjet printing, screen printing and aerosol jet printing etc, make it feasible to print a variety of sensor patterns. The electromechanical response of these sensors was used to measure strain/stress or damage of composite structures under various load conditions expected to be experienced by aircraft. These unique conductive polymer sensors provide a feasible, near real time monitoring system for composites without adding significant additional weight to the structure.

Breathable barrier textiles for both chemical agent and moisture are being actively developed for military and industrial applications. An ideal approach is to coat textiles with a semi-permeable film that allows the transport of water while still serving as a barrier for chemical agents. Sulfonated poly (styrene-block-isobutylene-block-styrene) (SIBS) copolymer spontaneously phase separates upon drying from solution to produce a nanostructured film with the controlled barrier functionality for water permeation and repelling of chemical agents.

The objective of this research is to investigate coating uniformity and phase morphology of SIBS coating materials fabricated by novel solvent combinations. Scanning electron microscopy analysis is used for the assessment of the coating uniformity as well as the level of adhesion between the polymer coating and fabric substrate. Transmission electron microscopy is used to characterize the phase separation morphology of the SIBS copolymer coating. The mechanical behavior of the coated fabric is determined through tensile and shear tests and is compared to the bare fabric behavior. The goal of this study is to relate the processing conditions of the final nanostructured block copolymer coated fabric produced on industrial scale.

Assembly of nanoparticles from bioactive peptides, caseinophosphopeptides (CPPs) and chitosan (CS) at physiological conditions and various CS/CPPs mass ratios have been systematically studied using a combination of turbidimetric titration, dynamic light scattering (DLS), electrophoretic mobility (zeta-potential) and transmission electron microscopy (TEM). Peptides, incorporated with CS forming nanoparticles, have already been prepared and identified using liquid chromatography-tandem mass spectrometry (LC-MS-MS). They are characteristic with different amount of clusters of phosphorylated seryl residues. At low salt concentration, an increase of CS/CPP mass ratio shifted the critical pHϕ1, which designated the formation of CS/CPP nanocomplexes, as well as pHmax, representing the neutralization of positive and negative charge to higher pH values. The peptide-polymer binding mechanism was analyzed according to the results of DLS, electrophoretic mobility, and TEM. First, negatively charged CPPs absorbed to positively charged CS molecular chain to form intrapolymer nanocomplexes saturated with CPPs (CPPNP). Then, the negatively charged CPPNP was bridged by added positively charged CS. Finally, novel nano-scaled spherical brushes were formed as additional CS molecule absorbed back to and bound the CPPNP. Phosphorylated groups in the CPPs might be the dominant sites for interaction with –NH3+ on the CS molecular chain.

Multi-component small molecule systems that are amphiphilic or that can hydrogen bond end-to-end or side-to-side have been shown to self-assemble into a variety of shapes including fibers, rods, sheets, plates, spheres, and tubes. Recently, we have identified a simple route to self-assemble the same shapes from one-component systems. The structures form by attaching ethyl vinyl sulfone (EVS) to amino acids in water at room temperature. Choice of amino acid, amount of EVS substitution, and solvent conditions determine the final shape. Functionalized amino acids spontaneously form structures like fibers, spheres, tubes, and donuts when dried from solution. Here we focus on fibers and tubes.