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This paper focuses on the study of the effect of aging on the composition of the solutions used for deposition of silane films onto metals. Such films are used for corrosion protection and adhesion applications. The silane films interact with metallic surfaces by reactions between the OH groups of both materials with elimination of water. Therefore, prior to the immersion of the metal into the silane solution, the silane has to be hydrolysed in order to generate a maximum of silanol (SiOH) groups, while minimizing condensation leading to siloxane (SiOSi) groups. One of the main factors influencing the amounts of silanol and siloxane groups produced is the solution aging. This paper demonstrates by NMR spectroscopy that in the case of a bridged silane, namely bis-1,2-(triethoxysilyl)ethane, a stable plateau offering a good compromise between hydrolysis and condensation in the solution is obtained between 24 h and a few days of aging.

No abstract is provided for this article.

The aim of this work is to study the physical self-healing properties of shape memory polyurethanes (SMPUs) with cerium ions on top of a pure aluminum substrate. To achieve this, the ‘odd random phase multisine’ electrochemical impedance spectroscopy (EIS) is used. The additional information given by this technique (stochastic noise, non-linear and non-stationary behavior of the sample during the measurement) has been useful to verify the quality of the measurement. Moreover, combined with a fitting algorithm weighted by the stochastic noise, these elements of information proved powerful in rejecting, accepting or improving electrical equivalent circuit models used to fit the impedance spectra. These SMPU consist of two parts: a soft matrix in caprolactone and a hard part in polyurethane. SMPU with 12, 30 and 41% of hard phase were investigated. The results showed that a physical self-healing can be observed for the coating with 12% of hard phase.

A variety of ceramic fabrics bearing mudstone inclusions (either naturally existing in the clay or added as temper) are attested in several sites in South-Western (SW) Cyprus. Within the Mamonia terrane of SW Cyprus mudstone-bearing lithologies are divided into two main groups. Sediments of the Ayios Photios group (sandstones, siltstones, mudstones, calcarenites, occasional limestones and chert) were deposited in marine conditions and close to the continental slope. In contrast, the contemporaneous Dhiarizos group contains radiolarian mudstones and cherts deposited in deep-sea conditions. Mudstones and cherts from both formations share similar macroscopic characteristics (distinctive red colour, fine texture) and can be confused for one another, especially when examined only as small-scale ceramic inclusions. Being able to differentiate between the different inclusion types and to link them to one of the two formations leads to useful conclusions regarding the provenance of ceramic samples within the Mamonia terrane. In this case study, geological samples from relevant mudstone sources were analysed as reference materials to describe the possible types of mudstone inclusions. Sr and Pb isotopic data were the primary means for distinguishing between the two major formations, as they closely relate to the differences in depositional setting. Based on the established isotopic classification, microtextural analysis and elemental mapping data were also compared to determine if members of the two formations are distinguishable at this level. Finally, as the isotopic approach proved to be the one offering better results, a theoretical outline for utilizing this type of information to determine the provenance of mudstones in ceramic sherds is presented.

Colour properties of barrier anodic oxide films on Al and Ti are studied. The anodised systems are described using the L*a*b* scale, total reflectance (TR) and spectroscopic ellipsometry (SE). SE is performed in the visual wavelength range and allows simultaneous determination of thickness and refractive index of the anodically formed oxide film. Subsequently SE results predict TR well and prove that the colours are obtained from interference effects. Anodised Ti shows much higher colour saturation than anodised Al. The difference in colour appearance is explained in terms of different reflectance of both metals; it depends less on the difference in refractive index of the oxides.

Hydrogen embrittlement leads to mechanical degradation of metals. Hence, hydrogen sorption/desorption properties of metals need to be characterized. An electrochemical procedure based on cyclic voltammetry (CV) and potentiostatic polarization is elaborated on plain-carbon steel. The procedure consists of first two consecutive CV cycles (pretreatment and reference CV), followed by cathodic H-charging, and subsequent CV scans to study and quantify the H-sorption/desorption. Best practice in this procedure is to perform all steps consecutively without interruption or sample manipulations between steps to avoid spontaneous H-loss. The H-related interaction with the steel is clearly identified in the CV and can be differentiated from the electrolyte contribution coming from thiourea. The study confirms the role of thiourea as H-recombination poison in alkaline solution, and also demonstrates that it contributes to the CV response. Additionally, various charging times are investigated to study the time to H-saturation, and also the scan rate during the CV procedure is varied to study time-related phenomena. Dedicated discharging experiments were included in the study to complement the CV data, giving additional insights in the H-steel interaction. Moreover, hydrogen related findings are successfully verified by using a complimentary method, i.e. hot extraction. The better understanding of the peaks in the CV and the continuous procedure result in a reliable methodology to characterize the H-sorption/desorption in steel.

Different pre-treatment procedures of the iron surface have been developed with the intention to alter the iron/Ppy interfacial properties. These results were correlated with the impedance response of Ppy coated iron samples in a corrosive aqueous environment.

The use of conductive polymers in aluminium electrolytic capacitors prevents leakage and enlarges the temperature use range when compared with their liquid counterparts. PEDOT:PSS is an outstanding candidate due to its tunable properties, i.e., electronic conductivity (10−5 to 103 S/cm), and its high thermal stability. As a result of their synthesis, PEDOT:PSS dispersions are characterized by a low pH value, which can influence pH sensitive materials such as aluminium. However, no work to date has studied the interaction between PEDOT:PSS dispersions and aluminium oxide substrates. In this work, the interface and interaction between PEDOT:PSS and an aluminium electrode were studied for the first time via odd random phase electrochemical impedance spectroscopy and analysed post mortem by SEM and AFM characterization. PEDOT:PSS dispersions at different pH values (1.9, 4.9, 5.8) were applied in a layered manner onto a non-etched aluminium substrate with a grown oxide layer on top, which provided a model system for the analysis of the interface. The analysis showed that the acidic PEDOT:PSS dispersions attacked the aluminium substrate, forming pores on the surface, but had a positive impact on the capacitance of the aluminium oxide/PEDOT:PSS systems. On the other hand, neutral dispersions did not affect the aluminium electrode, but showed poor layer formation properties, and the electrochemical analysis displayed a dispersion of results ranging from capacitive to resistive behaviour.

The appearance of materials and objects is important in for example household products, furniture, cars. Industries constantly adjust their fabrication parameters in order to create materials displaying the required properties. This is very time consuming and can be optimized with optical models. In literature optical models are to simulate the reflection of surfaces, but these reflections are never linked to their visual perception. In this research we aspire to create a link between the optical models and the visual perception of the surface. Steel was chosen as a case study because of its use in a wide variety of applications where the appearance of the steel is of paramount importance. Two parts are discerned in this paper: first different degrees of roughness were introduced on the steel substrates. Secondly a transparent coating is applied on the rough surfaces. The experimental data were used to predict the reflection of the surface.

A new experimental approach to study nanoparticle size distributions in electrochemical deposition processes by in-situ Small Angle X-ray Scattering (SAXS) is presented. A specifically designed flow cell was used to acquire SAXS frames after different nucleation and growth pulses in a potentiostatic multiple pulse approach. Measurements show that after a correct background subtraction, scattered intensity variations are only caused by electrodeposited silver nanoparticles and that size distribution evolution derived after modeling the SAXS data is in agreement with electrochemical particle growth.