Mihaela Vasilica

Dr. Mihaela Vasilica

Department of General Chemistry, University Politehnica of Bucharest, Bucuresti, Romania
orcid

Research Focus & Metrics

Academic Career Length

17Years (2010-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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16 April 2023 in Materials
Verified
Journal Article
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Mihaela VasilicaMihaela Vasilica
Mihaela Vasilica
ASAndrei Bogdan Stoian
Andrei Bogdan Stoian
RMRoberta Geanina Miftode
Roberta Geanina Miftode
RTRoxana Trușcă
Roxana Trușcă
EVEugeniu Vasile
Eugeniu Vasile
In this study, TiO2 thin films formed by dip-coating on an FTO substrate were obtained and characterized using surface, optical and electrochemical techniques. The impact of the dispersant (polyethylene glycol-PEG) on the surface (morphology, wettability, surface energy), optical (band gap and Urbach energy) and electrochemical (charge-transfer resistance, flat band potential) properties were investigated. When PEG was added to the sol–gel solution, the optical gap energy of the resultant films was reduced from 3.25 to 3.12 eV, and the Urbach energy increased from 646 to 709 meV. The dispersant addition in the sol–gel process influences surface features, as evidenced by lower contact-angle values and higher surface energy achieved for a compact film with a homogenous nanoparticle structure and larger crystallinity size. Electrochemical measurements (cycle voltammetry, electrochemical impedance spectroscopy and the Mott–Schottky technique) revealed improved catalytic properties of the TiO2 film, due to a higher insertion/extraction rate of protons into the TiO2 nanostructure, as well as a decrease in charge-transfer resistance from 418 k to 23.4 k and a decrease in flat band potential from 0.055 eV to −0.019 eV. The obtained TiO2 films are a promising alternative for technological applications, due to their advantageous surface, optical and electrochemical features.

25 May 2010 in Molecular Crystals and Liquid Crystals
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Journal Article
Closed access
Cristian PirvuCristian Pirvu
Cristian Pirvu
Mihaela VasilicaMihaela Vasilica
Mihaela Vasilica
SPSimona Popescu
Simona Popescu
Ioana DemetrescuIoana Demetrescu
Ioana Demetrescu
The aim of this work is to study the influence of surfactants concentration on pyrrole polimerization on Ti6Al7Nb alloy in order to improve the surface performance of such biomaterials. The electrochemical stability of the polypyrrole based composite coatings were evaluated in Hank's Balanced Salt Solution by Tafel tests, cycle voltammetry and electrochemical impedance spectroscopy (EIS). The surface analysis of composite coating type atomic force microscopy (AFM), was completed with an infrared structure evaluation. The coating properties such as electrochemical parameters, wettability and roughness can be controlled by changing the pyrrole/poly(styrene sulphonate) polymerization ratio.

5 December 2023 in Materials
Verified
Journal Article
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RMRoberta Geanina Miftode
Roberta Geanina Miftode
Camelia UngureanuCamelia Ungureanu
Camelia Ungureanu
VSVeronica Satulu
Veronica Satulu
Mihaela VasilicaMihaela Vasilica
Mihaela Vasilica
This study shows an easy way to use electrochemistry and plasma layering to make Cobalt-Blue-TiO2 nanotubes that are better at catalysing reactions. Once a titanium plate has been anodized, certain steps are taken to make oxygen vacancies appear inside the TiO2 nanostructures. To find out how the Co deposition method changed the final catalyst’s properties, it was put through electrochemical tests (to find the charge transfer resistance and flat band potential) and optical tests (to find the band gap and Urbach energy). The catalysts were also described in terms of their shape, ability to stick to surfaces, and ability to inhibit bacteria. When Cobalt was electrochemically deposited to Blue-TiO2 nanotubes, a film with star-shaped structures was made that was hydrophilic and antibacterial. The band gap energy went down from 3.04 eV to 2.88 eV and the Urbach energy went up from 1.171 eV to 3.836 eV using this electrochemical deposition method. Also, photodegradation tests with artificial doxycycline (DOX) water were carried out to see how useful the study results would be in real life. These extra experiments were meant to show how the research results could be used in real life and what benefits they might have. For the bacterial tests, both gram-positive and gram-negative bacteria were used, and BT/Co-E showed the best response. Additionally, photodegradation and photoelectrodegradation experiments using artificial doxycycline (DOX) water were conducted to determine the practical relevance of the research findings. The synergistic combination of light and applied potential leads to 70% DOX degradation after 60 min of BT/Co-E irradiation.

16 January 2026 in Materials
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Journal Article
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Cristina DumitriuCristina Dumitriu
Cristina Dumitriu
SPSimona Popescu
Simona Popescu
RMRoberta Geanina Miftode
Roberta Geanina Miftode
APAngela Păun
Angela Păun
Andreea Madalina PandeleAndreea Madalina Pandele
Andreea Madalina Pandele
Mihaela VasilicaMihaela Vasilica
Mihaela Vasilica
Y-branched TiO2 nanotubes (NTs) were produced by anodizing titanium plates derived from aerospace production leftovers and subsequently engineered to develop an enhanced TiO2-based photocatalytic system. The NTs were electrochemically reduced to obtain reduced TiO2 nanotubes (rTN) with a narrowed bandgap, followed by surface modification with polydopamine (PD) and silk fibroin-derived quantum dots (QDs) to promote enhanced UV and visible-light photocatalysis for wastewater treatment. The QDs were hydrothermally synthesized from Bombyx mori silk fibroin. Scanning Electron Microscopy (SEM) revealed spherical QD agglomerates encapsulated within the PD layer, while Energy Dispersive X-ray Spectroscopy (EDX) confirmed the presence of carbon and nitrogen originating from both PD and QD. The resulting rNT/PD/QD photocatalyst exhibited a significantly reduced bandgap (1.03 eV), increased Urbach energy (1.35 eV), and moderate hydrophilicity. A high double-layer capacitance (Cdl) indicated an enlarged electrochemically active surface due to the combination of treatments. Electrochemical characterization demonstrated reduced electrical resistance, higher charge density, and lower electron–hole recombination, leading to improved interfacial charge transfer efficiency and electrochemical stability during multi-cycle cyclic voltammetry measurements. Preliminary photocatalytic tests show that the rNT/PD/QD photocatalyst achieved a degradation efficiency of 79.26% for methyl orange (MO) and 35% for tetracycline (TC).

11 July 2023 in Preprints.org
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Preprint
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RMRoberta Geanina Miftode
Roberta Geanina Miftode
Camelia UngureanuCamelia Ungureanu
Camelia Ungureanu
VSVeronica Satulu
Veronica Satulu
Mihaela VasilicaMihaela Vasilica
Mihaela Vasilica
This study presents a straightforward electrochemical and plasma deposition method for producing Cobalt-doped Blue-TiO2 nanotubes with enhanced catalytic properties. After a titanium plate has been anodized, specific procedures are carried out that cause oxygen vacancies to form inside the TiO2 nanostructures. The obtained catalysts were subjected to electrochemical tests (to identify charge transfer resistance and flat band potential), optical analysis (to determine the band gap and Urbach energy) and also characterized in terms of morphology, wettability and antibacterial effect in order to understand and analyze the impact of the Co doping method on the final catalyst characteristics. A hydrophilic film with star-shaped structures and with antibacterial effect was created when cobalt was electrochemically doped to Blue-TiO2 nanotubes. By using this electrochemical doping technique, the Urbach energy was raised from 1.171 to 3.836 eV while the band gap energy was decreased from 3.04 to 2.88 eV. Additionally, photodegradation experiments using artificial doxycycline (DOX) water were conducted to determine the practical relevance of the research findings. In areas like antimicrobial applications and photodegradation of DOX, these extra experiments aimed to show the practical applicability and potential advantages of the research findings.