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Giovanni Marletta - One of the best experts on this subject based on the ideXlab platform.

  • Polymer Crystallization on Nanocurved Substrates: Distortion Versus Dewetting
    The Journal of Physical Chemistry C, 2019
    Co-Authors: Roberta Ruffino, Nunzio Tuccitto, Grazia M. L. Messina, Erika Kozma, Marinella Catellani, Giovanni Li-destri, Giovanni Marletta
    Abstract:

    The Crystallization of a model semicrystalline polymer, namely, poly-3-hexylthiophene (P3HT), was studied as a function of the curvature at the nanometric scale and substrate surface free energy (SFE). Nanostructured substrates with a controlled local curvature were prepared by deposition of a 235 nm SiO2 particle monolayer, and their SFE was modulated by functionalization with octadecyltrichlorosilane, followed by radiofrequency plasma oxidation. The Crystallization of ultrathin P3HT thin films, on the curved portions of the substrate, was found to mostly depend on the substrate SFE, while spontaneous wetting occurred in all cases. The effect is analyzed in terms of the interplay of polymer wetting (affecting the interfacial free energy) and lamellar Crystallization, implying the modulation of Crystallization Enthalpy, demonstrating that the balance between SFE minimization and Crystallization Enthalpy maximization governs the phenomenon. The results highlight the role played by the surface nanostructuri...

  • Polymer Crystallization on Nanocurved Substrates: Distortion Versus Dewetting
    2019
    Co-Authors: Roberta Ruffino, Nunzio Tuccitto, Grazia M. L. Messina, Erika Kozma, Marinella Catellani, Giovanni Li-destri, Giovanni Marletta
    Abstract:

    The Crystallization of a model semicrystalline polymer, namely, poly-3-hexylthiophene (P3HT), was studied as a function of the curvature at the nanometric scale and substrate surface free energy (SFE). Nanostructured substrates with a controlled local curvature were prepared by deposition of a 235 nm SiO2 particle monolayer, and their SFE was modulated by functionalization with octadecyltrichlorosilane, followed by radiofrequency plasma oxidation. The Crystallization of ultrathin P3HT thin films, on the curved portions of the substrate, was found to mostly depend on the substrate SFE, while spontaneous wetting occurred in all cases. The effect is analyzed in terms of the interplay of polymer wetting (affecting the interfacial free energy) and lamellar Crystallization, implying the modulation of Crystallization Enthalpy, demonstrating that the balance between SFE minimization and Crystallization Enthalpy maximization governs the phenomenon. The results highlight the role played by the surface nanostructuring in driving soft matter organization

Roberta Ruffino - One of the best experts on this subject based on the ideXlab platform.

  • Polymer Crystallization on Nanocurved Substrates: Distortion Versus Dewetting
    The Journal of Physical Chemistry C, 2019
    Co-Authors: Roberta Ruffino, Nunzio Tuccitto, Grazia M. L. Messina, Erika Kozma, Marinella Catellani, Giovanni Li-destri, Giovanni Marletta
    Abstract:

    The Crystallization of a model semicrystalline polymer, namely, poly-3-hexylthiophene (P3HT), was studied as a function of the curvature at the nanometric scale and substrate surface free energy (SFE). Nanostructured substrates with a controlled local curvature were prepared by deposition of a 235 nm SiO2 particle monolayer, and their SFE was modulated by functionalization with octadecyltrichlorosilane, followed by radiofrequency plasma oxidation. The Crystallization of ultrathin P3HT thin films, on the curved portions of the substrate, was found to mostly depend on the substrate SFE, while spontaneous wetting occurred in all cases. The effect is analyzed in terms of the interplay of polymer wetting (affecting the interfacial free energy) and lamellar Crystallization, implying the modulation of Crystallization Enthalpy, demonstrating that the balance between SFE minimization and Crystallization Enthalpy maximization governs the phenomenon. The results highlight the role played by the surface nanostructuri...

  • Polymer Crystallization on Nanocurved Substrates: Distortion Versus Dewetting
    2019
    Co-Authors: Roberta Ruffino, Nunzio Tuccitto, Grazia M. L. Messina, Erika Kozma, Marinella Catellani, Giovanni Li-destri, Giovanni Marletta
    Abstract:

    The Crystallization of a model semicrystalline polymer, namely, poly-3-hexylthiophene (P3HT), was studied as a function of the curvature at the nanometric scale and substrate surface free energy (SFE). Nanostructured substrates with a controlled local curvature were prepared by deposition of a 235 nm SiO2 particle monolayer, and their SFE was modulated by functionalization with octadecyltrichlorosilane, followed by radiofrequency plasma oxidation. The Crystallization of ultrathin P3HT thin films, on the curved portions of the substrate, was found to mostly depend on the substrate SFE, while spontaneous wetting occurred in all cases. The effect is analyzed in terms of the interplay of polymer wetting (affecting the interfacial free energy) and lamellar Crystallization, implying the modulation of Crystallization Enthalpy, demonstrating that the balance between SFE minimization and Crystallization Enthalpy maximization governs the phenomenon. The results highlight the role played by the surface nanostructuring in driving soft matter organization

Casparus Johan R. Verbeek - One of the best experts on this subject based on the ideXlab platform.

  • Modification of poly(lactic acid) using itaconic anhydride by reactive extrusion
    European Polymer Journal, 2015
    Co-Authors: K. I. Ku Marsilla, Casparus Johan R. Verbeek
    Abstract:

    Abstract Itaconic anhydride (IA) was grafted onto poly(lactic acid) (PLA) using dicumyl peroxide (DCP) as radical initiator using free-radical grafting. Different concentrations of monomer (2–6 wt.%) and initiator (0.5–0.75 wt.%) at 180 and 200 °C were used for chemical modification. Grafting was confirmed using titration and the highest degree of grafting was 0.75%. The degree of grafting increased gradually with increasing IA and DCP concentration, with minimal chain scission. Reaction kinetics showed that the initial rate of reaction was between 0.024 and 0.03 (l/mol s) 1/2 , depending on temperature. Grafted PLA showed a significant change in Enthalpy of Crystallization, Enthalpy of fusion as well as increased tensile strength and elongation at break accompanied by a reduction in stiffness.

Dmitri V. Louzguine-luzgin - One of the best experts on this subject based on the ideXlab platform.

  • Investigation of Zr55Cu30Al10Ni5 bulk amorphous alloy Crystallization
    Journal of Alloys and Compounds, 2019
    Co-Authors: Ruslan Sergiienko, Oleksandr A. Shcheretskyi, Vladislav Yu. Zadorozhnyy, Anatolii M. Verkhovliuk, Dmitri V. Louzguine-luzgin
    Abstract:

    Abstract The process of transition of the Zr55Cu30Al10Ni5 bulk amorphous alloy from an amorphous into a crystalline state has been investigated by using differential scanning calorimetry and dynamic mechanical analysis. The parameters of Crystallization of the alloy, such as glass transition temperature (Tg), Crystallization temperature (Tx), activation energy of Crystallization (Ea), solidus and liquidus temperatures (Tsol, Tliq), Crystallization Enthalpy (ΔНх), melting heat (ΔHm) and solidification heat (ΔHsol) have been determined. The behavior of the storage modulus (EI), the loss factor (tan δ) with a temperature change from room temperature to 873 K has been studied. The phase structure of the alloy after Crystallization was investigated by using X-ray diffraction.

Elizabete F. Lucas - One of the best experts on this subject based on the ideXlab platform.

  • Effect of Pressure on the Crystallization of Crude Oil Waxes. I. Selection of Test Conditions by Microcalorimetry
    Energy & Fuels, 2010
    Co-Authors: Lenise C. Vieira, Maria B. Buchuid, Elizabete F. Lucas
    Abstract:

    Evaluations of the potential for formation of wax deposits in laboratories generally are performed on stabilized oil samples, that is, at atmospheric pressure and without the presence of light components. Therefore, the effects to two important factors that influence the solubility of waxes, namely light fractions and pressure, are not considered. As a consequence, the results may not reflect what really happens in production lines and equipment. The high-pressure microcalorimetry technique (HPμDSC) is indicated for determining the wax appearance temperature (WAT) and Crystallization Enthalpy of waxes in oils, but due to the complexity of petroleum systems, the reliability of the results depends on the experimental conditions chosen. This paper reports experiments to evaluate the factors that influence the accuracy of the experimental results for determining the WAT and Crystallization Enthalpy of samples of Brazilian crude oil and condensate, saturated with different types of gases, by using high pressur...

  • Effect of Pressure on the Crystallization of Crude Oil Waxes. II. Evaluation of Crude Oils and Condensate
    Energy & Fuels, 2010
    Co-Authors: Lenise C. Vieira, Maria B. Buchuid, Elizabete F. Lucas
    Abstract:

    Laboratory analyses of the formation of wax deposits in crude oil are generally performed at atmospheric pressure on stabilized samples without the presence of light components. Therefore, the effects of two important factors that influence the solubility of waxes, namely, light fractions and pressure, are not considered. As a consequence, the results may not reflect what really happens in production lines and equipment. In this work, we evaluated five Brazilian crude oil samples and one condensate, recombined with different gases and under varying pressures, using the high-pressure microcalorimetry technique (HPμDSC). The samples were characterized with regard to the distribution of waxes by the number or carbon atoms to correlate with the results for wax appearance temperature (WAT) and Crystallization Enthalpy. The results indicate that rising pressure causes the WAT to rise as well and the recombination with gases composed mainly of light hydrocarbons reduces the WAT. Methane has the greatest influenc...