M. Lanza - Academia.edu (original) (raw)
Papers by M. Lanza
Nanomaterials and Nanotechnology, 2011
The synthesis of carbon nanotubes (CNTs) by chemical vapor deposition (CVD) of isobutane (i-C4H10... more The synthesis of carbon nanotubes (CNTs) by chemical vapor deposition (CVD) of isobutane (i-C4H10) over sodium-exchanged K10-montmorillonite based ironcatalysts is investigated. By studying the influence of iron-addition (5-25 wt%) on the catalyst performances, at 700 °C, an empirical relationship is derived relating the mass of CNTs synthesized with the exposed surface of loaded iron, as resulting from simultaneous change of number, size and dispersion of Fe-nanoparticles available for the growth.
physica status solidi (a), 2010
... Fe-catalysed synthesis of C nanotubes by i-C 4 H 10 decomposition: Advantages and problems de... more ... Fe-catalysed synthesis of C nanotubes by i-C 4 H 10 decomposition: Advantages and problems deriving from H 2 addition to the growth ambient. Saveria Santangelo 1,* ,; Candida Milone 2 ,;Maurizio Lanza 3 ,; Giacomo Messina 1. Article first published online: 7 JUN 2010. ...
Materials Science and Engineering: A, 2004
An investigation of the thermal and mechanical characteristics of new full-interpenetrating polym... more An investigation of the thermal and mechanical characteristics of new full-interpenetrating polymer networks (full-IPNs), prepared by simultaneous and sequential synthesis paths, has been performed in the temperature regions above and below the glass transition. It has been observed that simultaneous full-IPNs exhibit higher values of density than sequential full-IPNs, as a consequence of an enhanced intermolecular packing. This peculiarity leads to an increase of the glass transition temperature and to a larger "␥-suppression" effect for the ␥ 2 -relaxation characterizing the polycyanurate phase of simultaneous full-IPNs, which has been ascribed to reduction of the free-volume available for the molecular group rearrangements.
Journal of Non-Crystalline Solids, 2002
Differential scanning calorimetry and dynamic mechanical spectroscopy studies have been performed... more Differential scanning calorimetry and dynamic mechanical spectroscopy studies have been performed between 120 and 600 K in a new series of sequential full-interpenetrating polymer networks (full-IPNs) of crosslinked polyurethane and polycyanurate network (PCN), based on dicyanate ester of 1,1 0 -bis-4,cyanatophenyl-ethane. The measurements have revealed the existence of two distinct glass transitions in the thermograms and of relaxation losses given by the overlap of two a a -relaxations in the mechanical spectra whose temperature locations change with changing weight ratio of polymeric component. These observations indicate that the morphology of this new class of full-IPNs is based on double-phase structures characterized by weak interchain interactions. The interpenetration affects markedly the glass transition temperatures revealed in the pure components as a consequence of modifications in the local environments of the relaxing molecular units in the two phases. Below the glass transition, two secondary relaxation losses have been observed which have been ascribed to local molecular transitions within each polymeric component. The analysis of their concentration behaviors leads to a conclusion that the interpenetration process affects markedly the local motion of the PCN component.
Journal of Nanoscience and Nanotechnology, 2010
The synthesis of C nanotubes by catalyzed chemical vapor deposition at 600 degrees C is investiga... more The synthesis of C nanotubes by catalyzed chemical vapor deposition at 600 degrees C is investigated, using yield and purity degree of C deposits to monitor the reaction outcome. From the reaction, carried out in C4H10-H2-He environment over Al2O3 supported Fe catalysts, multi-walled C nanotubes are attained, which, after purification, are analyzed by routinely-used diagnostics techniques. In order to clarify the role of the growth parameters, various experiments are performed changing flow rates of reactive gases, as well as, amount, metal load and reduction temperature of Fe/Al2O3 catalysts in the ranges 15-90 cc/min, 0.25-2.00 g, 10-40 wt% and 500-700 degrees C, respectively. Correspondingly, carbon yield varies between 47 wt% and 913 wt%, while purity degree between 56 wt% and 93 wt%. Owing to the lack of any correlation between these changes, it is initially quite difficult to envisage the effect, produced by any change of the growth conditions, on the final reaction outcome. The problem is solved by applying a semi-empirical approach, through which the "original" growth variables are combined to give dimensionless arguments (scaling laws for the reaction parameters), able to account for all the variation of yield and purity in the ranges considered. As final result, the growth issue can be easily predicted because carbon yield and purity degree can be approximated through very simple functions of the "new" process variables.
Journal of Materials Research, 1997
... e Tecnologie Fisiche Avanzate, Istituto Nazionale per la Fisica della Materia (INFM), Salita ... more ... e Tecnologie Fisiche Avanzate, Istituto Nazionale per la Fisica della Materia (INFM), Salita Sperone 31, I-98166 cp 57 S. Agata, Messina, Italy G. Di Marco and M. Lanza Istituto di ... By means of ax2 minimization procedure we identify two Auger sub-bands at 499.1 and at 500.7 eV ...
Diamond and Related Materials, 2009
Diamond and Related Materials, 2012
ABSTRACT This work is a continuation and a completion of a previous study on the synthesis of mul... more ABSTRACT This work is a continuation and a completion of a previous study on the synthesis of multi-walled carbon nanotubes by iron-catalyzed chemical vapor deposition over sodium-exchanged K10-montmorillonite (Na+-K10) based catalysts. The influence of iron-addition (5–25 wt.%) on the catalyst performances is investigated. By comparing results here obtained by isobutane decomposition at 700 °C with those previously achieved at 600 °C by using Fe/Al2O3 catalysts upon the same gas-flowing setup (120 cm3/min 1:1 i-C4H10 + H2), it comes out that although in both the cases the best catalytic performance is obtained for a relative (to iron) carbon-supply of ≈ 160 wt.%/min, higher specific yield is achieved over alumina supported catalysts. The possible reasons for this difference are discussed in the light of the most recent assessments on nanotube growth.
Surface-enhanced Raman scattering (SERS) takes advantage of the giant electromagnetic field enhan... more Surface-enhanced Raman scattering (SERS) takes advantage of the giant electromagnetic field enhancement provided by localized surface plasmons in metal nanoparticles to amplify the weak Raman scattering of the molecules. Optical fibers coated with noble metal nanoparticles can therefore be used as SERS-based sensors for remote detection of molecular species. In this article, we report on the development of an optical fiber SERS sensor capable to operate on a range of excitation wavelengths from the visible to the near-infrared. We introduce a quasistatic chemical etching protocol to engineer the tip shape and investigate the effects of the tip shape on the sensor performances.
The European Physical Journal Applied Physics, 2008
ABSTRACT
Nanomaterials and Nanotechnology, 2011
The synthesis of carbon nanotubes (CNTs) by chemical vapor deposition (CVD) of isobutane (i-C4H10... more The synthesis of carbon nanotubes (CNTs) by chemical vapor deposition (CVD) of isobutane (i-C4H10) over sodium-exchanged K10-montmorillonite based ironcatalysts is investigated. By studying the influence of iron-addition (5-25 wt%) on the catalyst performances, at 700 °C, an empirical relationship is derived relating the mass of CNTs synthesized with the exposed surface of loaded iron, as resulting from simultaneous change of number, size and dispersion of Fe-nanoparticles available for the growth.
physica status solidi (a), 2010
... Fe-catalysed synthesis of C nanotubes by i-C 4 H 10 decomposition: Advantages and problems de... more ... Fe-catalysed synthesis of C nanotubes by i-C 4 H 10 decomposition: Advantages and problems deriving from H 2 addition to the growth ambient. Saveria Santangelo 1,* ,; Candida Milone 2 ,;Maurizio Lanza 3 ,; Giacomo Messina 1. Article first published online: 7 JUN 2010. ...
Materials Science and Engineering: A, 2004
An investigation of the thermal and mechanical characteristics of new full-interpenetrating polym... more An investigation of the thermal and mechanical characteristics of new full-interpenetrating polymer networks (full-IPNs), prepared by simultaneous and sequential synthesis paths, has been performed in the temperature regions above and below the glass transition. It has been observed that simultaneous full-IPNs exhibit higher values of density than sequential full-IPNs, as a consequence of an enhanced intermolecular packing. This peculiarity leads to an increase of the glass transition temperature and to a larger "␥-suppression" effect for the ␥ 2 -relaxation characterizing the polycyanurate phase of simultaneous full-IPNs, which has been ascribed to reduction of the free-volume available for the molecular group rearrangements.
Journal of Non-Crystalline Solids, 2002
Differential scanning calorimetry and dynamic mechanical spectroscopy studies have been performed... more Differential scanning calorimetry and dynamic mechanical spectroscopy studies have been performed between 120 and 600 K in a new series of sequential full-interpenetrating polymer networks (full-IPNs) of crosslinked polyurethane and polycyanurate network (PCN), based on dicyanate ester of 1,1 0 -bis-4,cyanatophenyl-ethane. The measurements have revealed the existence of two distinct glass transitions in the thermograms and of relaxation losses given by the overlap of two a a -relaxations in the mechanical spectra whose temperature locations change with changing weight ratio of polymeric component. These observations indicate that the morphology of this new class of full-IPNs is based on double-phase structures characterized by weak interchain interactions. The interpenetration affects markedly the glass transition temperatures revealed in the pure components as a consequence of modifications in the local environments of the relaxing molecular units in the two phases. Below the glass transition, two secondary relaxation losses have been observed which have been ascribed to local molecular transitions within each polymeric component. The analysis of their concentration behaviors leads to a conclusion that the interpenetration process affects markedly the local motion of the PCN component.
Journal of Nanoscience and Nanotechnology, 2010
The synthesis of C nanotubes by catalyzed chemical vapor deposition at 600 degrees C is investiga... more The synthesis of C nanotubes by catalyzed chemical vapor deposition at 600 degrees C is investigated, using yield and purity degree of C deposits to monitor the reaction outcome. From the reaction, carried out in C4H10-H2-He environment over Al2O3 supported Fe catalysts, multi-walled C nanotubes are attained, which, after purification, are analyzed by routinely-used diagnostics techniques. In order to clarify the role of the growth parameters, various experiments are performed changing flow rates of reactive gases, as well as, amount, metal load and reduction temperature of Fe/Al2O3 catalysts in the ranges 15-90 cc/min, 0.25-2.00 g, 10-40 wt% and 500-700 degrees C, respectively. Correspondingly, carbon yield varies between 47 wt% and 913 wt%, while purity degree between 56 wt% and 93 wt%. Owing to the lack of any correlation between these changes, it is initially quite difficult to envisage the effect, produced by any change of the growth conditions, on the final reaction outcome. The problem is solved by applying a semi-empirical approach, through which the "original" growth variables are combined to give dimensionless arguments (scaling laws for the reaction parameters), able to account for all the variation of yield and purity in the ranges considered. As final result, the growth issue can be easily predicted because carbon yield and purity degree can be approximated through very simple functions of the "new" process variables.
Journal of Materials Research, 1997
... e Tecnologie Fisiche Avanzate, Istituto Nazionale per la Fisica della Materia (INFM), Salita ... more ... e Tecnologie Fisiche Avanzate, Istituto Nazionale per la Fisica della Materia (INFM), Salita Sperone 31, I-98166 cp 57 S. Agata, Messina, Italy G. Di Marco and M. Lanza Istituto di ... By means of ax2 minimization procedure we identify two Auger sub-bands at 499.1 and at 500.7 eV ...
Diamond and Related Materials, 2009
Diamond and Related Materials, 2012
ABSTRACT This work is a continuation and a completion of a previous study on the synthesis of mul... more ABSTRACT This work is a continuation and a completion of a previous study on the synthesis of multi-walled carbon nanotubes by iron-catalyzed chemical vapor deposition over sodium-exchanged K10-montmorillonite (Na+-K10) based catalysts. The influence of iron-addition (5–25 wt.%) on the catalyst performances is investigated. By comparing results here obtained by isobutane decomposition at 700 °C with those previously achieved at 600 °C by using Fe/Al2O3 catalysts upon the same gas-flowing setup (120 cm3/min 1:1 i-C4H10 + H2), it comes out that although in both the cases the best catalytic performance is obtained for a relative (to iron) carbon-supply of ≈ 160 wt.%/min, higher specific yield is achieved over alumina supported catalysts. The possible reasons for this difference are discussed in the light of the most recent assessments on nanotube growth.
Surface-enhanced Raman scattering (SERS) takes advantage of the giant electromagnetic field enhan... more Surface-enhanced Raman scattering (SERS) takes advantage of the giant electromagnetic field enhancement provided by localized surface plasmons in metal nanoparticles to amplify the weak Raman scattering of the molecules. Optical fibers coated with noble metal nanoparticles can therefore be used as SERS-based sensors for remote detection of molecular species. In this article, we report on the development of an optical fiber SERS sensor capable to operate on a range of excitation wavelengths from the visible to the near-infrared. We introduce a quasistatic chemical etching protocol to engineer the tip shape and investigate the effects of the tip shape on the sensor performances.
The European Physical Journal Applied Physics, 2008
ABSTRACT