C2P2

Designing new approaches to incorporate dopant impurities in semiconductor materials is essential in keeping pace with electronics miniaturization without device performance degradation. On the basis of a mild solution-phase synthetic approach to functionalize silica nanoparticles, we were able to graft tailor-made boronmolecular precursors and control the thermal release of boron in the silica framework. The molecular-level description of the surface structure lays the foundation for a structure−property relationship approach, which is readily and successfully implemented to dope non-deglazed silicon wafers. As the method does not require an additional oxide capping step and shows minimal risk of carbon contamination, as demonstrated by compositional and electrical characterizations of the wafers, it is perfectly adapted to advanced microelectronics manufacturing processes.

Highly active nonpromoted W-based hydrotreating catalysts are prepared through a molecular approach with a control of each step. This approach yields WS 2 crystallites exhibiting hexagonal 2D morphology, which have been characterized by combining XPS and HR HAADF-STEM techniques and ab initio molecular modeling. The first step is the impregnation of a welldefined precursor, [W(OEt) 5 ] 2 , grafted onto partially dehydroxylated amorphous silica−alumina (ASA) and characterized at the molecular level by spectroscopic techniques (NMR and IR). The use of increasing amounts of W precursor reveals the formation of (i) a layer of tungsten surface species grafted on the surface and (ii) layers of more mobile adsorbed species loosely bonded to the surface. Sulfidation of these materials provides WS 2 supported on ASA, which shows unprecedented lower sulfidation temperatures down to ambient temperature and improved activity by comparison with conventional references (polyoxometalate route). In addition, these improved activities are explained not only by a better level of sulfidation but also by the 2D hexagonal-like morphology of WS 2 crystallites (revealed by HR HAADF-STEM), in contrast to a truncated triangle-like morphology for conventional samples. This molecular approach thus opens new avenues to understand and improve the performances of hydrotreating catalysts.

A novel spraying apparatus was developed to obtain reproducible free sprayed films. Aqueous solutions of PolyVinyl Alcohol PVA 4-98, HydroxyPropyl MethylCellulose HPMC 603 and HPMC 615 were used as reference coating materials. The apparatus is composed by a spraying system, a closed chamber containing a rotating Teflon cylinder, a pressured air supply system, a spray solution supply system, and a computerized control system. The spraying air pressure, the cylinder rotation speed, and the cylinder-spray nozzle distance were tailored in such a manner that the roughness of the obtained free films was similar to that from reference coated particles. Optimum spraying process conditions were found for all three coating materials using design of experiments. The morphology of the sprayed films obtained using the optimum conditions is evaluated by means of scanning electron microscopy (SEM), and atomic force microscopy (AFM), and then compared with those from corresponding cast films and coating layers on particles. A match was found between the morphology of sprayed films and that from the corresponding coating layer on the particle surface. The spray apparatus produced reproducible sprayed films with tuneable roughness and/or smoothness depending on the set of processing parameters.

Hydroxypropyl methylcellulose (HPMC) and polyvinyl alcohol (PVA) are important polymers in pharmaceutical, food and other industries being largely used as encapsulation agents. The characterization of two reference grades of HPMC (Pharmacoat Ò 603 and Pharmacoat Ò 615) and one reference grade of PVA (Mowiol Ò 4-98), through X-ray diffraction (XRD) and thermogravimetry (TG) is described. Specific analyses were performed by means of dynamic vapour sorption analysis of water adsorption/ desorption from vapours at 10, 25, 40, 55 and 70°C. Guggenheim-Anderson-de Boer (GAB), Brunauer-Emmett-Teller (BET), Park and n-layer BET models were successfully used to fit the experimental data. The glass transition temperature as function of water content was measured by means of differential scanning calorimetry (DSC). The experimental data were analysed according to Linear, Gordon-Taylor, Fox and Roos equations. XRD studies revealed amorphous structure for the Pharmacoat Ò 603 and Pharmacoat Ò 615 and crystalline for Mowiol Ò 4-98. Single and multi-step temperature degradation point was found for Pharmacoat Ò 603 and Pharmacoat Ò 615 and Mowiol Ò 4-98, respectively. The water uptake is higher for Pharmacoat Ò 603 and Pharmacoat Ò 615 than Mowiol Ò 4-98. The influence of temperature on water uptake is opposite for the two types of polymers. GAB and n-layer BET were found to better model Pharmacoat Ò 603 and Pharmacoat Ò 615 and Mowiol Ò 4-98 data, respectively. The water makes the glass transition to decrease quite drastically. Gordon-Taylor is better fitting the experimental data both for Pharmacoat Ò 603 and Pharmacoat Ò 615 and Mowiol Ò 4-98.