1. Introduction and overview 2. Film stress and substrate curvature 3. Stress in anisotropic and patterned films 4. Delamination and fracture 5. Film buckling, bulging and peeling 6. Dislocation formation in epitaxial systems 7. Dislocation interactions and strain relaxation 8. Equilibrium and stability of surfaces 9. The role of stress in mass transport.

Thin Film Materials: Stress, Defect Formation and Surface Evolution

Porous anodic aluminum oxide: anodization and templated synthesis of functional nanostructures.

Manufactured nanoparticles: An overview of their chemistry, interactions and potential environmental implications

This work received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement no. REGPOT-CT2012-316331-POLARIS. The work was also funded by FEDER through the Competitive Factors Operational Program (COMPETE) and by National funds through the Portuguese Foundation for Science and Technology (FCT) in the scope of the projects PTDC/FIS/115048/2009 and PTDC/CTM-BIO/1814/2012. The authors gratefully acknowledge Dr. Luca Gasperini (3B's Research Group, University of Minho, Portugal) for his help with the figures.

Molecular Interactions Driving the Layer-by-Layer Assembly of Multilayers

Ongoing advances in nanotechnology research have established a variety of methods to synthesize nanoparticles (NPs) from a diverse range of materials, including metals, semiconductors, ceramics, metal oxides, polymers, etc. Depending upon their origin and synthesis methods, NPs possess unique physicochemical, structural and morphological characteristics, which are important in a wide variety of applications concomitant to electronic, optoelectronic, optical, electrochemical, environment and biomedical fields. This review provides a comprehensive overview on various physical, chemical and bio-assisted methods largely employed to synthesize and fabricate NPs of varying size, surface characteristics, functionalities and physicochemical behavior. The key applications of nanoparticles have also been discussed.

Methods and strategies for the synthesis of diverse nanoparticles and their applications: a comprehensive overview

We report a controllable strain gauge factor obtained using a two-dimensional nanoparticle layer formed from platinum nanoparticles A vacuum technique is used for room temperature nanoparticle deposition that allows control of the electrical resistance of the film, exhibiting semiconducting-like behavior when nanoparticle arrays cover the surface below a threshold value while above it a metallic behavior is prevalent The highest sensitivity is obtained for intermediate density values of the nanoparticle assemblies, which could be explained using a tunneling and hopping current expression The device, which exhibits more than one order of magnitude higher strain sensitivity than continuous metallic films, is fabricated at room temperature through standard lithographic processing allowing for miniaturization and easy integration in silicon technology or flexible substrates

https://iopscience.iop.org/article/10.1088/0957-4484/23/28/285501/pdf

High strain sensitivity controlled by the surface density of platinum nanoparticles

Direct and high spatial resolution printing of polymer/carbon nanotube (CNT) composite layers has been demonstrated by means of laser induced forward transfer (LIFT). Laser irradiation of composite target materials, such as poly(acrylic acid)/CNT and polyvinylpyrrolidone/CNT, enabled dry deposition of well resolved composite pixels onto glass substrates. The dispersion of the CNT into the deposited composite pixels was investigated by transmission electron microscopy. The LIFT technique was also employed for the accurate deposition of polymer/CNT composite pixels onto aluminum microelectrodes for the fabrication of chemical sensors based on polymer/CNT compounds.

Polymer/carbon nanotube composite patterns via laser induced forward transfer

The present work is focused on the sol–gel synthesis, characterization and catalytic performance evaluation of novel Mg-Ce-Zr-O-based mixed oxides supported Rh catalysts for the purification of H 2 -rich gas streams from phenol through steam reforming in the 575–730 °C range. Phenol is used as a model compound of tars, the former being one of the main constituents of tars formed during steam gasification and pyrolysis of biomass. Novel Rh catalysts (0.1 wt%) supported on Mg-Ce-Zr-O-based mixed oxides modified by alkaline-earth, rare earth, and transition metal ions, having the general formula Mg-Ce-Zr-X-O (where X stands for La, Sr, Ba, Ca and Zn) were systematically studied. The physicochemical properties of the catalysts were evaluated using complementary bulk and surface characterization techniques, such as BET, XPS, in situ XRD, TEM/SAED and SEM/EDX. Transient techniques including H 2 -TPR, TPD-CO 2 and TPD-NH 3 were employed in order to characterize redox behavior, surface basicity, and surface acidity of support, respectively. Among the catalysts examined, a 0.1 wt% Rh/40Mg-20Ce-20Zr-20La-O was found to exhibit the highest hydrogen product yield, specific H 2 production rate (μmol/m 2  min), and the lowest CO/CO 2 product ratio (575–730 °C), even when compared to a Ni-based commercial steam reforming of tars catalyst. At 655 °C, a H 2 yield of ∼95% and a specific reaction rate of 100 μmol H 2 /m 2  min were obtained for a feed containing 0.5 vol% phenol and 40 vol% H 2 O at a gas hourly space velocity of ∼80,000 h −1 . This activity behavior is correlated with the largest concentration of basic sites and labile oxygen species (μmol/m 2 ), and also with the largest acid/base site ratio present in the 40Mg-20Ce-20Zr-20La-O support composition. Steam was also found to be an efficient reagent for the removal of carbonaceous deposits (e.g., C x H y ) formed on the catalyst surface during phenol steam reforming. The H/C atom compositional ratio of the carbonaceous deposits was found to depend on reaction temperature.

Tailoring MgO-based supported Rh catalysts for purification of gas streams from phenol

Ultra-thin alumina films with self-ordered cylindrical vertical pores were fabricated on a p-type silicon substrate by anodization of Al films with thickness in the range of 30–500 nm in sulfuric or oxalic acid aqueous solutions. In both cases the pores were arranged in hexagonal cells in a close-packed structure and their diameter and density depended on the electrochemical solution used. In the case of sulfuric acid both 30 and 500 nm Al films resulted in a similar uniform porous structure using exactly the same anodization conditions for both thicknesses, the pore diameter being in the range of 10–30 nm and their density of the order of 6–8 × 1010 pores cm−2. In the case of oxalic acid the 500 nm thick films resulted in a uniform porous structure with larger pores than in sulfuric acid, of diameter in the range of 20–40 nm and a density of the order of . On the other hand, with oxalic acid it was impossible to form a uniform porous structure from the 30 nm thick Al film at the same conditions as used for the 500 nm thick film. Plan-view and cross-sectional transmission electron microscopy was used to investigate systematically the structure and morphology of the alumina films. Cross-sectional TEM images showed that the alumina/Si interface was sharp, but a void was observed beneath each pore, separated from the pore by a thin alumina layer. The same structure was obtained with both electrolytes. The effect of pre-annealing of the Al films on the anodic alumina layers was also investigated in detail.

https://iopscience.iop.org/article/10.1088/0957-4484/16/1/021/pdf

Ultra-thin porous anodic alumina films with self-ordered cylindrical vertical pores on a p-type silicon substrate

Since its invention, electron microscope has been a valuable tool in the development of scientific theory and it contributed greatly to biology, medicine and material sciences. This wide spread use of electron microscopes is based on the fact that they permit the observation and characterization of materials on a nanometer (nm) to micrometer ()m) scale. This paper presents the basic theory for electron microscopy, focusing on the two basic types of Ems; SEM, TEM.

/pdf/electron-microscopy-the-basics-11i7xyz1gh.pdf

Konstantinos P. Giannakopoulos

Papers

High strain sensitivity controlled by the surface density of platinum nanoparticles

Polymer/carbon nanotube composite patterns via laser induced forward transfer

Tailoring MgO-based supported Rh catalysts for purification of gas streams from phenol

Ultra-thin porous anodic alumina films with self-ordered cylindrical vertical pores on a p-type silicon substrate

Electron Microscopy: The Basics