I. Tacchini - Academia.edu (original) (raw)
Papers by I. Tacchini
Plant Physiology, 2011
The surface of peach (Prunus persica 'Calrico') is covered by a dense indumentum, which may serve... more The surface of peach (Prunus persica 'Calrico') is covered by a dense indumentum, which may serve various protective purposes. With the aim of relating structure to function, the chemical composition, morphology, and hydrophobicity of the peach skin was assessed as a model for a pubescent plant surface. Distinct physicochemical features were observed for trichomes versus isolated cuticles. Peach cuticles were composed of 53% cutan, 27% waxes, 23% cutin, and 1% hydroxycinnamic acid derivatives (mainly ferulic and p-coumaric acids). Trichomes were covered by a thin cuticular layer containing 15% waxes and 19% cutin and were filled by polysaccharide material (63%) containing hydroxycinnamic acid derivatives and flavonoids. The surface free energy, polarity, and work of adhesion of intact and shaved peach surfaces were calculated from contact angle measurements of water, glycerol, and diiodomethane. The removal of the trichomes from the surface increased polarity from 3.8% (intact surface) to 23.6% and decreased the total surface free energy chiefly due to a decrease on its nonpolar component. The extraction of waxes and the removal of trichomes led to higher fruit dehydration rates. However, trichomes were found to have a higher water sorption capacity as compared with isolated cuticles. The results show that the peach surface is composed of two different materials that establish a polarity gradient: the trichome network, which has a higher surface free energy and a higher dispersive component, and the cuticle underneath, which has a lower surface free energy and higher surface polarity. The significance of the data concerning water-plant surface interactions is discussed within a physiological context.
Hydrothermally synthesized titanate nanotubes were carbon-doped through a thermal treatment in th... more Hydrothermally synthesized titanate nanotubes were carbon-doped through a thermal treatment in the presence of glucose followed by blending with single-walled carbon nanotubes (SWCNTs). A series of TiO 2 -based materials was prepared with various initial glucose contents and two SWCNT types, resulting in total carbon contents from 0.3 wt.% to nearly 26 wt.%. Electron microscopy observations indicated that titanate nanotubes were converted into nanorods during the thermal treatment, and X-ray diffraction patterns confirmed that all the treated materials mostly consisted of anatase TiO 2 . Glucose pyrolysis caused changes in the infrared and X-ray photoelectron spectra of the titania material, indicating an interaction between the inserted carbon atoms and titanium atoms. Raman spectra of SWCNT/C/TiO 2 hybrids showed characteristic bands of both the SWCNT and anatase TiO 2 phases. SWCNT/C/TiO 2 multicomponent materials demonstrated substantially better photocatalytic activities than P...
Nano Brief Reports and Reviews, Aug 1, 2012
Single-walled carbon nanotube (SWCNT)/anatase TiO2 composite materials were prepared by successiv... more Single-walled carbon nanotube (SWCNT)/anatase TiO2 composite materials were prepared by successive sol–gel and hydrothermal processes. The composites contained thin SWCNT bundles embedded in aggregates of ~ 12 nm anatase crystallites. A series of SWCNT/ TiO2 photocatalysts was prepared with various SWCNT contents; a SWCNT content of ~ 8 wt.% was found to be optimal for methylene blue (MB) degradation under combined UV/visible radiation. The optimized SWCNT/ TiO2 composite demonstrated substantially higher photocatalytic activity than pure nanocrystalline anatase (5.2 times) and Degussa P-25 TiO2 powder (2.7 times). The MB degradation and mineralization processes were separately evaluated and complete decomposition of MB was shown to take place. The presence of SWCNTs caused an increase in the visible light absorbance of TiO2 ; however, SWCNT/ TiO2 composites did not show any photocatalytic activity when the UV part of the UV/visible light source was filtered. Therefore SWCNTs worked as acceptors for the TiO2 photoexcited electrons, but did not act as sensitizers for TiO2 .
Master de iniciacion a la investigacion en ingenieria quimica y tecnologias del medio ambiente
Physical Chemistry Chemical Physics, 2011
We report on femtosecond-nanosecond (fs-ns) studies of the triphenylamine organic dye (TPC1) inte... more We report on femtosecond-nanosecond (fs-ns) studies of the triphenylamine organic dye (TPC1) interacting with titania nanoparticles of different sizes, nanotubes and nanorods. We used time-resolved emission and absorption spectroscopy to measure the photoinduced dynamics of forward and back electron transfer processes taking place in TPC1-titania complexes in acetonitrile (ACN) and dichloromethane (DCM) solutions. We observed that the electron injection from the dye to titania occurs in a multi-exponential way with the main contribution of 100 fs from the hot excited charge-transfer state of anchored TPC1. This process competes with the relaxation of the excited state, mainly governed by solvation, that takes place with average time constants of 400 fs in ACN and 1.3 ps in DCM solutions. A minor contribution to the electron injection process takes place with longer time constants of about 1-10 ps from the relaxed excited state of TPC1. The latter times and their contribution do not depend on the size of the nanoparticles, but are substantially smaller in the case of nanotubes (1-3 ps), probably due to the caging effect. The contribution is also smaller in DCM than in ACN. The efficient back recombination takes place also in a multi-exponential way with times of 1 ps, 15 ps and 1 ns, and only 20-30% of the initial injected electrons in the conduction band are left within the first 1 ns after excitation. The faster recombination rates are suggested due to those originating from the free electrons in the conduction band of titania or the electrons in the shallow trap states, while the slower recombination is due to the electrons in the deep trap states. The results reported here should be relevant to a better understanding of the photobehaviour of an organic dye with promising potential for use in solar cells. They should also help to determine the important factors that limit the efficiency of solar cells based on the triphenylamine-based dyes for solar energy conversion. Electronic supplementary information (ESI) available: -S18 and Tables S1-S5. Femtosecond time-resolved emission studies of TPC1 in ACN at high concentration. Global analysis of femtosecond transient absorption studies of free TPC1 in ACN. Concentration effect on femtosecond transient absorption studies of free TPC1 in ACN. Femtosecond transient absorption studies of free TPC1 in DCM. Principal SVD component analysis. See
Micro & Nano Letters, 2011
Materials Science and Engineering: B, 2012
Journal of Materials Science, 2011
Talanta, 2008
Networks of different carbon nanotube (CNT) materials were investigated as resistive gas sensors ... more Networks of different carbon nanotube (CNT) materials were investigated as resistive gas sensors for NO 2 detection. Sensor films were fabricated by airbrushing dispersions of double-walled and multi-walled CNTs (DWNTs and MWNTs, respectively) on alumina substrates. Sensors were characterized by resistance measurements from 25 to 250 • C in air atmosphere in order to find the optimum detection temperature.
Carbon, 2009
The experimental parameters involved in the formation of the Ni catalytic nanoparticles on Si/SiO... more The experimental parameters involved in the formation of the Ni catalytic nanoparticles on Si/SiO 2 substrates that seed carbon nanotube growth were investigated. It was found that after deposition of a nickel film on the substrate, the temperature and time of the thermal and reduction catalyst pre-treatment steps are crucial variables for optimized nanoparticle distribution with different average diameters, depending on the initial film thickness. Densely-packed carbon nanotube forests with interesting potential applications have been grown from this nanoparticle distribution. (M.T. Martínez). C A R B O N 4 7 ( 2 0 0 9 ) 1 9 8 9 -2 0 0 1 a v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / c a r b o n
Building and Environment, 2011
PLANT PHYSIOLOGY, 2011
The surface of peach (Prunus persica 'Calrico') is covered by a dense indumentum, which may serve... more The surface of peach (Prunus persica 'Calrico') is covered by a dense indumentum, which may serve various protective purposes. With the aim of relating structure to function, the chemical composition, morphology, and hydrophobicity of the peach skin was assessed as a model for a pubescent plant surface. Distinct physicochemical features were observed for trichomes versus isolated cuticles. Peach cuticles were composed of 53% cutan, 27% waxes, 23% cutin, and 1% hydroxycinnamic acid derivatives (mainly ferulic and p-coumaric acids). Trichomes were covered by a thin cuticular layer containing 15% waxes and 19% cutin and were filled by polysaccharide material (63%) containing hydroxycinnamic acid derivatives and flavonoids. The surface free energy, polarity, and work of adhesion of intact and shaved peach surfaces were calculated from contact angle measurements of water, glycerol, and diiodomethane. The removal of the trichomes from the surface increased polarity from 3.8% (intact surface) to 23.6% and decreased the total surface free energy chiefly due to a decrease on its nonpolar component. The extraction of waxes and the removal of trichomes led to higher fruit dehydration rates. However, trichomes were found to have a higher water sorption capacity as compared with isolated cuticles. The results show that the peach surface is composed of two different materials that establish a polarity gradient: the trichome network, which has a higher surface free energy and a higher dispersive component, and the cuticle underneath, which has a lower surface free energy and higher surface polarity. The significance of the data concerning water-plant surface interactions is discussed within a physiological context.
Plant Physiology, 2011
The surface of peach (Prunus persica 'Calrico') is covered by a dense indumentum, which may serve... more The surface of peach (Prunus persica 'Calrico') is covered by a dense indumentum, which may serve various protective purposes. With the aim of relating structure to function, the chemical composition, morphology, and hydrophobicity of the peach skin was assessed as a model for a pubescent plant surface. Distinct physicochemical features were observed for trichomes versus isolated cuticles. Peach cuticles were composed of 53% cutan, 27% waxes, 23% cutin, and 1% hydroxycinnamic acid derivatives (mainly ferulic and p-coumaric acids). Trichomes were covered by a thin cuticular layer containing 15% waxes and 19% cutin and were filled by polysaccharide material (63%) containing hydroxycinnamic acid derivatives and flavonoids. The surface free energy, polarity, and work of adhesion of intact and shaved peach surfaces were calculated from contact angle measurements of water, glycerol, and diiodomethane. The removal of the trichomes from the surface increased polarity from 3.8% (intact surface) to 23.6% and decreased the total surface free energy chiefly due to a decrease on its nonpolar component. The extraction of waxes and the removal of trichomes led to higher fruit dehydration rates. However, trichomes were found to have a higher water sorption capacity as compared with isolated cuticles. The results show that the peach surface is composed of two different materials that establish a polarity gradient: the trichome network, which has a higher surface free energy and a higher dispersive component, and the cuticle underneath, which has a lower surface free energy and higher surface polarity. The significance of the data concerning water-plant surface interactions is discussed within a physiological context.
Hydrothermally synthesized titanate nanotubes were carbon-doped through a thermal treatment in th... more Hydrothermally synthesized titanate nanotubes were carbon-doped through a thermal treatment in the presence of glucose followed by blending with single-walled carbon nanotubes (SWCNTs). A series of TiO 2 -based materials was prepared with various initial glucose contents and two SWCNT types, resulting in total carbon contents from 0.3 wt.% to nearly 26 wt.%. Electron microscopy observations indicated that titanate nanotubes were converted into nanorods during the thermal treatment, and X-ray diffraction patterns confirmed that all the treated materials mostly consisted of anatase TiO 2 . Glucose pyrolysis caused changes in the infrared and X-ray photoelectron spectra of the titania material, indicating an interaction between the inserted carbon atoms and titanium atoms. Raman spectra of SWCNT/C/TiO 2 hybrids showed characteristic bands of both the SWCNT and anatase TiO 2 phases. SWCNT/C/TiO 2 multicomponent materials demonstrated substantially better photocatalytic activities than P...
Nano Brief Reports and Reviews, Aug 1, 2012
Single-walled carbon nanotube (SWCNT)/anatase TiO2 composite materials were prepared by successiv... more Single-walled carbon nanotube (SWCNT)/anatase TiO2 composite materials were prepared by successive sol–gel and hydrothermal processes. The composites contained thin SWCNT bundles embedded in aggregates of ~ 12 nm anatase crystallites. A series of SWCNT/ TiO2 photocatalysts was prepared with various SWCNT contents; a SWCNT content of ~ 8 wt.% was found to be optimal for methylene blue (MB) degradation under combined UV/visible radiation. The optimized SWCNT/ TiO2 composite demonstrated substantially higher photocatalytic activity than pure nanocrystalline anatase (5.2 times) and Degussa P-25 TiO2 powder (2.7 times). The MB degradation and mineralization processes were separately evaluated and complete decomposition of MB was shown to take place. The presence of SWCNTs caused an increase in the visible light absorbance of TiO2 ; however, SWCNT/ TiO2 composites did not show any photocatalytic activity when the UV part of the UV/visible light source was filtered. Therefore SWCNTs worked as acceptors for the TiO2 photoexcited electrons, but did not act as sensitizers for TiO2 .
Master de iniciacion a la investigacion en ingenieria quimica y tecnologias del medio ambiente
Physical Chemistry Chemical Physics, 2011
We report on femtosecond-nanosecond (fs-ns) studies of the triphenylamine organic dye (TPC1) inte... more We report on femtosecond-nanosecond (fs-ns) studies of the triphenylamine organic dye (TPC1) interacting with titania nanoparticles of different sizes, nanotubes and nanorods. We used time-resolved emission and absorption spectroscopy to measure the photoinduced dynamics of forward and back electron transfer processes taking place in TPC1-titania complexes in acetonitrile (ACN) and dichloromethane (DCM) solutions. We observed that the electron injection from the dye to titania occurs in a multi-exponential way with the main contribution of 100 fs from the hot excited charge-transfer state of anchored TPC1. This process competes with the relaxation of the excited state, mainly governed by solvation, that takes place with average time constants of 400 fs in ACN and 1.3 ps in DCM solutions. A minor contribution to the electron injection process takes place with longer time constants of about 1-10 ps from the relaxed excited state of TPC1. The latter times and their contribution do not depend on the size of the nanoparticles, but are substantially smaller in the case of nanotubes (1-3 ps), probably due to the caging effect. The contribution is also smaller in DCM than in ACN. The efficient back recombination takes place also in a multi-exponential way with times of 1 ps, 15 ps and 1 ns, and only 20-30% of the initial injected electrons in the conduction band are left within the first 1 ns after excitation. The faster recombination rates are suggested due to those originating from the free electrons in the conduction band of titania or the electrons in the shallow trap states, while the slower recombination is due to the electrons in the deep trap states. The results reported here should be relevant to a better understanding of the photobehaviour of an organic dye with promising potential for use in solar cells. They should also help to determine the important factors that limit the efficiency of solar cells based on the triphenylamine-based dyes for solar energy conversion. Electronic supplementary information (ESI) available: -S18 and Tables S1-S5. Femtosecond time-resolved emission studies of TPC1 in ACN at high concentration. Global analysis of femtosecond transient absorption studies of free TPC1 in ACN. Concentration effect on femtosecond transient absorption studies of free TPC1 in ACN. Femtosecond transient absorption studies of free TPC1 in DCM. Principal SVD component analysis. See
Micro & Nano Letters, 2011
Materials Science and Engineering: B, 2012
Journal of Materials Science, 2011
Talanta, 2008
Networks of different carbon nanotube (CNT) materials were investigated as resistive gas sensors ... more Networks of different carbon nanotube (CNT) materials were investigated as resistive gas sensors for NO 2 detection. Sensor films were fabricated by airbrushing dispersions of double-walled and multi-walled CNTs (DWNTs and MWNTs, respectively) on alumina substrates. Sensors were characterized by resistance measurements from 25 to 250 • C in air atmosphere in order to find the optimum detection temperature.
Carbon, 2009
The experimental parameters involved in the formation of the Ni catalytic nanoparticles on Si/SiO... more The experimental parameters involved in the formation of the Ni catalytic nanoparticles on Si/SiO 2 substrates that seed carbon nanotube growth were investigated. It was found that after deposition of a nickel film on the substrate, the temperature and time of the thermal and reduction catalyst pre-treatment steps are crucial variables for optimized nanoparticle distribution with different average diameters, depending on the initial film thickness. Densely-packed carbon nanotube forests with interesting potential applications have been grown from this nanoparticle distribution. (M.T. Martínez). C A R B O N 4 7 ( 2 0 0 9 ) 1 9 8 9 -2 0 0 1 a v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / c a r b o n
Building and Environment, 2011
PLANT PHYSIOLOGY, 2011
The surface of peach (Prunus persica 'Calrico') is covered by a dense indumentum, which may serve... more The surface of peach (Prunus persica 'Calrico') is covered by a dense indumentum, which may serve various protective purposes. With the aim of relating structure to function, the chemical composition, morphology, and hydrophobicity of the peach skin was assessed as a model for a pubescent plant surface. Distinct physicochemical features were observed for trichomes versus isolated cuticles. Peach cuticles were composed of 53% cutan, 27% waxes, 23% cutin, and 1% hydroxycinnamic acid derivatives (mainly ferulic and p-coumaric acids). Trichomes were covered by a thin cuticular layer containing 15% waxes and 19% cutin and were filled by polysaccharide material (63%) containing hydroxycinnamic acid derivatives and flavonoids. The surface free energy, polarity, and work of adhesion of intact and shaved peach surfaces were calculated from contact angle measurements of water, glycerol, and diiodomethane. The removal of the trichomes from the surface increased polarity from 3.8% (intact surface) to 23.6% and decreased the total surface free energy chiefly due to a decrease on its nonpolar component. The extraction of waxes and the removal of trichomes led to higher fruit dehydration rates. However, trichomes were found to have a higher water sorption capacity as compared with isolated cuticles. The results show that the peach surface is composed of two different materials that establish a polarity gradient: the trichome network, which has a higher surface free energy and a higher dispersive component, and the cuticle underneath, which has a lower surface free energy and higher surface polarity. The significance of the data concerning water-plant surface interactions is discussed within a physiological context.