We propose a novel technique for electroless plating on polymer substrates using a dense CO2 beyond the critical point. Ni-P thin films were fabricated by a novel, hybrid technique consisting of two processes: catalyzation in supercritical CO2 with Pd bis-acetylacetonate and electroless plating in emulsion with dense carbon dioxide. Catalyzation in supercritical CO2 enabled the nucleation of a large number of Pd nuclei on a polyimide substrate without chemical pretreatment, and the deposition of a uniform Ni-P metal film. The electroless plating in emulsion with dense carbon dioxide produced a uniformly plated film without peeling or nodules. The improved uniformity was attained by the solubility and diffusivity of the dense CO2 beyond the critical point in the emulsion.

Hard coatings containing microscopic reservoirs for solid lubricant storage have the potential to advance the development of dry, self-lubricating coatings. In the present study we have investigated several methods for fabricating hard coatings that incorporate microscopic reservoirs. These methods all involve the use of placeholders on the substrate surface that are later removed after deposition of the hard coating. One method uses a solution containing ceramic beads, while the second method uses conventional photolithography methods. Coatings using both of these methods were fabricated using TiN as the hard coating. The effectiveness of the microreservoirs for solid lubricant storage was examined by conducting pin-on-disk test using various solid lubricants, including graphite and indium. The performance of coatings with random arrangements of microreservoirs was scattered while samples with the ordered arrangements of microreservoirs all performed well. Optical microscopy examination of the wear tracks showed the microreservoirs were generally successful at trapping the graphite lubricant during wear. With a sufficient density and appropriate distribution of the microreservoirs, the significant improvements in tribological performance can be realized.

The integration of optical interconnects in printed circuit boards (PCB) is a rapidly growing field worldwide due to a continuously increasing need for high-speed data transfer. There are any concepts discussed, among which are the integration of optical fibers or the generation of waveguides by UV lithography, embossing, or direct laser writing. The devices presented so far require many different materials and process steps, but particularly also highly-sophisticated assembly steps in order to couple the optoelectronic elements to the generated waveguides. In order to overcome these restrictions, an innovative approach is presented which allows the embedding of optoelectronic components and the generation of optical waveguides in only one optical material. This material is an inorganic-organic hybrid polymer, in which the waveguides are processed by two-photon absorption (TPA) processes, initiated by ultra-short laser pulses. In particular, due to this integration and the possibility of in situ positioning the optical waveguides with respect to the optoelectronic components by the TPA process, no complex packaging or assembly is necessary. Thus, the number of necessary processing steps is significantly reduced, which also contributes to the saving of resources such as energy or solvents. The material properties and the underlying processes will be discussed with respect to optical data transfer in PCBs.

Atomic layer deposition (ALD) was performed on quantities of multiwalled carbon nanotubes (MWCNTs) in a rotary reactor. Because of nucleation difficulties, Al2O3 ALD grew as nanospheres on the MWCNTs. After a NO2 nucleation treatment, Al2O3 ALD films grew conformally and noncovalently functionalized the surface of the MWCNT. This Al2O3 ALD film served as a platform for the growth of W ALD metal. The uncoated and ALD-coated MWCNTs were characterized with transmission electron microscopy and x-ray photoelectron spectroscopy. This study demonstrates that ALD can be performed on quantities of very high surface area MWCNT substrates.

The surface layer of titanium implants, i.e. titanium dioxide, is responsible for the inertness of titanium-based implants within the human body. However, their cytocompatibility properties and long-term efficacy are limited without further surface engineering since the average functional lifetime of an orthopedic implant is only 10 to 15 years. In this study, an electrochemical method known as anodization was used to create titania nanotubular structures on titanium implant surfaces. These nanotubes were about 60 nm wide (inner diameter) and 200 nm deep. In vitro studies found that anodized surfaces consisting of titania nanotube arrays were favored by bone-forming cells (osteoblasts) compared to unanodized surfaces. These titania nano-tubular structures were utilized here as novel drug release delivery systems. It is proposed that the system designed here can have multi-functional drug release to inhibit infection and wound inflammation while increasing new bone formation. For this purpose, antibiotic drugs (penicillin and streptomycin) were loaded into these nanotubular structures by physical adsorption. To mediate interactions between drug molecules and nanotube walls, anodized titanium nanotubes were modified by silanization to possess amine or methyl groups on their surface instead of −OH groups. Results showed increased hydrophobicity of chemically modified titania nanotubes (methyl > amine > hydroxyl terminated surface). These drug loaded substrates were soaked in phosphate buffered solution in a simulated body environment to determine drug release behavior. Buffer solutions were collected and replaced every day. The eluted drug amounts were measured spectroscopically. Results showed more antibiotic penicillin and streptomycin released from chemically modified nanotubes compared to unanodized titanium substrates; specifically, titania anodized nanotubes functionalized with −OH groups did quite well. In this manner, this study advances titanium currently used in orthopedics to possess drug release behavior which can improve orthopedic implant efficacy.

Capacitive humidity sensors were fabricated using interdigitated electrodes coated with amorphous nanostructured TiO2 thin films grown by glancing angle deposition. The sensor exhibited a large change in capacitance, increasing exponentially from ∼ 1 nF to ∼ 1 μF for an increase in relative humidity from 2 % to 92 %. A simple model of the capacitive response and dielectric constant of the devices has been developed and compared to the experimental results. From this comparison, it is clear that the magnitude of the device response observed cannot be explained with bulk dielectric constants or literature values.

The goal of this work is to investigate self-organization processes in molecular chains. Computer simulation has been performed by means of a molecular dynamics method. Morse potential was chosen as the potential of atomic interaction. Molecular chains were exposed to low-energy ion impact by two means: mono beam and plasma treatment. The amount of the energy transferred to molecules of the chain was varied in wide range but it must be less than the energy needed to break the chain. Chains with water molecules that were cut from microcrystal of ice (homogeneous chains) as well as net of hydrogen bonds (heterogeneous chains) were under our investigations. In last case areas with periodical structure symbolize embedded crystal nanoclusters in the whole disordered medium.

We showed that nonlinear oscillations become excited in the chains after low-energy ion impact and as a result of them molecules become stabilized in new positions, which results in the formation and development of new metastable molecular groups (nanoclusters). In homogenous chains formed nanoclusters correspond to elements of “molecular memory”. We showed that in homogeneous molecular chains critical energy needed for self-organization processes development is less than for nonlinear molecular chains with already embedded clusters. In this case nanocluster becomes an active zone which determines further self-organization processes. It is clusters that provide new complexes of physical and chemical properties. This computer model can be also used for simulation of low-energy ion impact on polymers and biological objects.

Effect of substrate on the texture of electrodeposited Ni layer was investigated by using various substrates; Ni-P alloy (amorphous), pure Cu (fcc) and pure Ni (fcc). In the case of Ni-P and Cu substrates, deposited Ni layer shows the (115) fiber texture and its formation was not biased by substrate. On the other hand, the formation of texture is not independent of Ni substrate because its texture is not ideal fiber.

Near the interface between deposited Ni layer and Ni-P or Cu substrates, fine columnar grains were observed. In contrast, on Ni substrate there are coarse columnar grains ahead of continuous epitaxial region. It is considered that texture of deposited Ni layer is not independent of Ni substrate due to the fact that these columnar grains satisfy a certain orientation relationship with respect to substrate.

Micro-scale woven structures were replicated 3 dimensionally by conformal coating onto natural woven cotton using a binary reaction of trimethylaluminum and water at 100°C. Even after the woven cotton was removed at 450°C, the woven structures completely remained. Results demonstrate the capability of ALD to penetrate into the complex 3D network structure of natural woven cotton to form uniform coating at low temperature and give insight into general understanding of methodology to translate deposition processes from 2D surface to a 3D network to obtain a uniform coating throughout the sample network bulk. It also shows the possibility of replication of micro-scale structures from highly conformal coatings to give the unique synthesis root of hollow structures.

Metal nanoparticles are of great importance in the fabrication of new nanocomposite materials. One area of increasing interest is the application of metal nanoparticles (NP) as substrates for surface enhanced Raman scattering (SERS). In this regard, self-assembled monolayers (SAMs) of sulfur containing organic compounds are ideal target for SERS studies due to the strong affinity of sulfur for noble metals. Two types of molecules were synthesized for this study, an organic-soluble and a water-soluble styrene derivative. Self-assembling behaviors of these monomers on gold or silver nanostructured surfaces at room temperature were studied by UV-Vis spectroscopy, dynamic light scattering (DLS), SERS spectroscopy, and scanning electron microscopy (SEM). It was found that the interaction between sulfur compounds and metal NPs is strongly dependent on the NP size and the monomer environment. The hydrophilic NP surface switches to hydrophobic upon binding of sulfur-containing monomers, which leads to the formation of aggregates in aqueous solution for both water-soluble and oil-soluble monomers. The self-assembling behavior of these monomers on the metallic surface was compared with that of the corresponding homopolymers. Due to macromolecular and steric effects, the binding interaction between homopolymer and metal NP is weaker than that between NP and monomers. Surface polymerization of these monomers on metallic surfaces was observed as supported by SERS. Core-shell nanoparticles could also be obtained through seeded emulsion polymerization, but a decrease in SERS activity was observed.

We demonstrated high temperature glancing deposition (HT-GLAD) of Al on the heated substrate with trench patterns. When Al was deposited under the condition, where the Al vapor is incident at very glancing on the sidewall but on the surface, Al nano-whiskers grew only on the sidewall of the trenches since HT-GLAD condition is achieved only for the sidewall. On the other, Al was deposited at glancing angle both on the surface and the sidewalls, nano-whiskers grow both on the surface and the sidewalls of the trenches. The selective growth of the nano-whisker is successfully achieved by controlling the geometrical deposition conditions. Remarkably, moreover, the nano-whiskers grow not only on the illuminated sidewalls but also on the shadow sidewall. In addition, few nano-whiskers grow on the shadow region of the bottom of the trenches. In order to understand the peculiar growth of Al nano-whiskers, novel transport processes of Al atoms other than the surface diffusion have to be clarified. The reevaporation or reflective scattering on the sidewalls of the trenches is likely to play an important role in the growth of nano-whiskers.

Novel surface engineering techniques of polymeric materials are essential to produce advanced topographies which could for example serve to modulate cell and tissue response in bio-materials. Direct Laser Interference Patterning (DLIP) permits the fabrication of repetitive arrays and microstructures by irradiation of the sample surface with coherent beams of light. Furthermore, the most important advantage of this method is that no additional process steps are required in comparison with other top-down or bottom-up techniques. In this study, we report a novel method for the advanced design of architectures in polymers using a single step process, as well as photo-activation of polymers with low absorption coefficient using a second polymer with relative high absorption coefficient. Previously calculated interference patterns using the well known interference theory could be directly produced on polymeric surface. Moreover, the cross-section of the structured polymers changes depending on the intensity of the laser beams, and photomachinability of polymers is highly influenced by laser wavelength. High absorbance of the polymeric materials at specific wavelengths allows the reduction of the laser intensity required to achieve a determined structure depth. For (60:40 %) polymethylmetacrylate/polystyrene copolymer substrate, different structures types were observed depending on the laser intensity including swelling and ablation of the material.

Joining between Nylon-film and Silicone-rubber was successfully developed. Effects of EB-irradiation on joining strength of different polymers without adhesive materials were investigated by using homogeneous EB irradiation. The EB irradiation increased the joining strength of the joining sample between Nylon-film and Silicone-rubber. Excess EB-irradiation more than 0.3 MGy apparently decreased the joining strength. To discuss the influences of electron beam irradiation on the joining strength, ESR signals related to dangling bonds were observed. Since the EB irradiation produced detectable dangling bonds on Nylon-film, using dangling bonds probably joined the different polymers.

The aim of the present study was to test the in vitro bioactive behavior of two new ternary mixtures consisting of a glass-ceramic porcelain, a bioactive glass and alumina (PBA) as coatings on dental glass ceramic substrates. They consisted of bioactive glass- in the system SiO2-Na2O-CaO-P2O5−, powder from a leucite-fluorapatite glass ceramic and γ-Al2O3 in 50-42.5-7.5 wt % respectively, while coatings with the same two components in 50-50 wt % ratio, without Al2O3, served as control. The characterization of the coatings was performed by Scanning Microscopy (SEM-EDS), Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction (XRD). The in vitro bioactivity was tested in Simulated Body Fluid (SBF) and the surfaces of reacted specimens were examined by SEM and FTIR. All coatings presented rough surface, while FTIR spectra revealed the characteristic peaks of the crystallized phases in the bioactive glass network and dental glass ceramic, i.e. Sodium Calcium Silicate (Na4Ca4Si6O18), Leucite (KAlSi2O6) and Fluorapatite (Ca5(PO4)3F), and furthermore the very limited participation of Al3+ in the bioactive glass network. In the coatings the main phases detected by XRD were, also, Na4Ca4Si6O18 and Leucite, dispersed in an amorphous glassy matrix. Furthermore, a transformation of γ-Al2O3 to δ-Al2O3 was observed and a new phase of Nepheline (Na7.15Al7.2Si8.8O32) was detected in traces. Apatite was developed sporadically on the surfaces of the PBA coatings after 30 days in SBF. These results demonstrate a slight retardation of bioactive response of the coatings of the ternary mixtures compared to dual ones consisting of dental glass ceramic and bioactive glass. The incorporation of Al2O3 can enhance the mechanical properties without a substantial degradation of bioactivity. This finding renders these coatings as promising composite materials for potential dental applications.

An attempt is made to understand the growth kinetics of carbon nanospheres (CNS) synthesized using a “green” technique. An aqueous solution of glucose, the precursor, was hydrothermally treated to produce porous CNS with homogeneous size distribution and smooth surfaces. The growth of CNS was studied by evaluating transmission electron microscope images as a function of hydrothermal reaction time and temperatures. Raman spectra revealed the presence of short-ordered graphitic nanostructures in an amorphous carbon matrix. FTIR spectroscopy confirms the carbonization of glucose and shows the presence of surface hydroxyl groups on CNSs. Based on various experimental observations it is proposed that the growth of CNSs is dictated by a reaction-controlled mechanism where long chain glucose-based oligomers bond to the CNS surface. The narrow size distribution and highly hydrophilic surface of these amorphous CNS makes them potential candidates for biomedical applications.

Layer-by-layer (LbL) assembly is used to create thin films by alternately exposing a substrate to positively- and negatively-charged molecules or particles in water. In recent years, LbL assemblies containing poly(3,4-ethylenedioxythiophene) (PEDOT) have been heavily studied, but little work has focused on improving the environmental stability of these thin films. Most intrinsically conductive polymers suffer from increasing resistance with exposure to ultraviolet light. In the present work, photolytic stability is improved by adding UV-absorbing nanoparticles to PEDOT assemblies. Films made by alternately depositing PEDOT-PSS and polyethylenimine (PEI) show an order of magnitude increase in sheet resistance after just 28 hours of exposure to 365 nm light. This degradation is cut in half by incorporating UV-absorbing nanoparticles, carbon black or titanium dioxide, into these assemblies. After more than 200 hours of exposure, films containing TiO2 nanoparticles have sheet resistance that is one fifth that of the unprotected PEDOT. In addition to adding UV-absorbing particles, the influence of doping and type of polycation on bulk resistivity and film growth were evaluated. These films are able to achieve bulk resistivity values below 1 Ohm cm with a thickness below 100 nm. When combined with transparency greater than 90%, these films may be useful for electrostatic dissipation layers or low conductivity electrodes in film or flexible display applications.

We have first developed useful Solvent-Induced Reprecipitation Process, and have first succeeded in fabricating C60 nano/microcrystals with various shape and size, using m-xylene and 2-propanol as good and poor solvents, respectively.

It was found that the resulting C60 nano/microcrystals had a hexagonal crystal structure, and that were a kind of crystal solvates in which the molar ratio of C60 to m-xylene was 3:2. C60 nano/microcrystals could be said to be important nano components of integrated devices in electronics.

The physical properties of resonant leaky modes in periodically patterned layered materials are summarized. Representative examples of photonic device applications including filters, polarizers, wideband reflectors, tunable elements, and biosensors are discussed.

A novel approach has been explored for the efficient dispersion and uniaxial alignment of fibers in dual phase polymer matrices based on the streaming flow that occurs when two immiscible polymer blends are melt processed under high shear conditions. Such conditions improve the alignment and distribution of fibers in the matrix, a feature of particular importance when fine nanofibers are used. This self-alignment mechanism seeks to produce optimum properties from relatively small volume fractions of fiber. Recent efforts have focused on a model system containing micron-size glass fibers in immiscible polymer blends. This paper presents selected mechanical properties measured for the model system and the flow/orientation paradigm that produces the observed morphologies.

We investigated epitaxial assembly in aggregates of BaTiO3 and CaTiO3 nanocrystals, which were synthesized under a hydrothermal condition at 150°C using distilled water-ethanol solvent, by transmission electron microscopy analysis. The volume ratio of distilled water-ethanol used as the solvent gives a significant influence on the crystal growth of the nanocrystals. The obtained results indicate that epitaxial assembly is surely involved in the crystal growth of BaTiO3 and CaTiO3 nanocrystals under the present thermal condition.