TY  - CONF
AU  - Božinović, Nevena
AU  - Rajić, Vladimir
AU  - Savva, K.
AU  - Potočnik, Jelena
AU  - Stratakis, E.
AU  - Petrović, S.
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11816
AB  - The experimental study of the dynamic femtosecond laser substrate pre-patterning of the Ti/Zr/Ti thin film system is reported. The design of surface pattering with the micrometer features in the form of spikes is investigated in order to improve the arrayed surface structures for biomedical applications. Femtosecond laser pulses were used to acquire black silicon surfaces decorated with conical structures (spikes) on crystalline silicon surfaces under 6.5×102 mbar of SF6 environmental atmosphere. After irradiation, the silicon surface exhibits high aspect ratio spikes, which have conical shapes of about 2 μm height, 40° angle opening, 13×106 cm−2 density that remains approximately uniform across the processed area. Results show that the base of the induced conical structures has an elliptical shape with a major (long) and minor (short) axis on the horizontal plane. It is revealed that the orientation of the long axis of the ellipsis is polarization-dependent with the long axis oriented always perpendicularly to the electric field of the laser beam. Spike formation has been attributed to a complex mechanism initiated by partial material melting and subsequent capillary wave formation driven by surface tension gradients within the molten region. Ion sputtering was used to create unique composite thin films on pre-patterned Si substrates that consist of two layers of Ti and subsurface layer of Zr on the interface of titanium. The total thickness of the deposited composite in Ti/Zr/Ti form was 300 nm. The composition, surface morphology and wetting properties were analyzed by scanning electron microscopy (SEM-EDS), profilometry and wettability measurements. The formation of micro-patterns with spikes array of composite Ti/Zr/Ti thin film systems was used to observe the effects of morphology on survival, adhesion and proliferation of the MRC-5 cell culture line. To determine whether Ti/Zr/Ti thin films have a toxic effect on living cells, an MTT assay was performed. The relative cytotoxic effect as a percentage of surviving cells showed that there was no difference in cell number between the Ti/Zr/Ti thin films and the control cells. There was also no difference in the viability of the MRC-5 cells.
PB  - Belgrade : Vinča Institute of Nuclear Sciences
C3  - PHOTONICA2023 : 9th International School and Conference on Photonics : book of abstracts; August 28 - September 1, 2023; Belgrade
T1  - Preparing the bioactive surface of Ti/Zr/Ti system by femtosecond laser pre-patterning of substrate
SP  - 117
EP  - 117
UR  - https://hdl.handle.net/21.15107/rcub_vinar_11816
ER  - 

@conference{
author = "Božinović, Nevena and Rajić, Vladimir and Savva, K. and Potočnik, Jelena and Stratakis, E. and Petrović, S.",
year = "2023",
abstract = "The experimental study of the dynamic femtosecond laser substrate pre-patterning of the Ti/Zr/Ti thin film system is reported. The design of surface pattering with the micrometer features in the form of spikes is investigated in order to improve the arrayed surface structures for biomedical applications. Femtosecond laser pulses were used to acquire black silicon surfaces decorated with conical structures (spikes) on crystalline silicon surfaces under 6.5×102 mbar of SF6 environmental atmosphere. After irradiation, the silicon surface exhibits high aspect ratio spikes, which have conical shapes of about 2 μm height, 40° angle opening, 13×106 cm−2 density that remains approximately uniform across the processed area. Results show that the base of the induced conical structures has an elliptical shape with a major (long) and minor (short) axis on the horizontal plane. It is revealed that the orientation of the long axis of the ellipsis is polarization-dependent with the long axis oriented always perpendicularly to the electric field of the laser beam. Spike formation has been attributed to a complex mechanism initiated by partial material melting and subsequent capillary wave formation driven by surface tension gradients within the molten region. Ion sputtering was used to create unique composite thin films on pre-patterned Si substrates that consist of two layers of Ti and subsurface layer of Zr on the interface of titanium. The total thickness of the deposited composite in Ti/Zr/Ti form was 300 nm. The composition, surface morphology and wetting properties were analyzed by scanning electron microscopy (SEM-EDS), profilometry and wettability measurements. The formation of micro-patterns with spikes array of composite Ti/Zr/Ti thin film systems was used to observe the effects of morphology on survival, adhesion and proliferation of the MRC-5 cell culture line. To determine whether Ti/Zr/Ti thin films have a toxic effect on living cells, an MTT assay was performed. The relative cytotoxic effect as a percentage of surviving cells showed that there was no difference in cell number between the Ti/Zr/Ti thin films and the control cells. There was also no difference in the viability of the MRC-5 cells.",
publisher = "Belgrade : Vinča Institute of Nuclear Sciences",
journal = "PHOTONICA2023 : 9th International School and Conference on Photonics : book of abstracts; August 28 - September 1, 2023; Belgrade",
title = "Preparing the bioactive surface of Ti/Zr/Ti system by femtosecond laser pre-patterning of substrate",
pages = "117-117",
url = "https://hdl.handle.net/21.15107/rcub_vinar_11816"
}

Božinović, N., Rajić, V., Savva, K., Potočnik, J., Stratakis, E.,& Petrović, S.. (2023). Preparing the bioactive surface of Ti/Zr/Ti system by femtosecond laser pre-patterning of substrate. in PHOTONICA2023 : 9th International School and Conference on Photonics : book of abstracts; August 28 - September 1, 2023; Belgrade
Belgrade : Vinča Institute of Nuclear Sciences., 117-117.
https://hdl.handle.net/21.15107/rcub_vinar_11816

Božinović N, Rajić V, Savva K, Potočnik J, Stratakis E, Petrović S. Preparing the bioactive surface of Ti/Zr/Ti system by femtosecond laser pre-patterning of substrate. in PHOTONICA2023 : 9th International School and Conference on Photonics : book of abstracts; August 28 - September 1, 2023; Belgrade. 2023;:117-117.
https://hdl.handle.net/21.15107/rcub_vinar_11816 .

Božinović, Nevena, Rajić, Vladimir, Savva, K., Potočnik, Jelena, Stratakis, E., Petrović, S., "Preparing the bioactive surface of Ti/Zr/Ti system by femtosecond laser pre-patterning of substrate" in PHOTONICA2023 : 9th International School and Conference on Photonics : book of abstracts; August 28 - September 1, 2023; Belgrade (2023):117-117,
https://hdl.handle.net/21.15107/rcub_vinar_11816 .

TY  - CONF
AU  - Gaković, Biljana M.
AU  - Petrović, S.
AU  - Peruško, Davor
AU  - Mimidis, A.
AU  - Kavatzikidou, E.
AU  - Stratakis, E.
PY  - 2018
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/12441
AB  - Femtosecond laser texturing holds promise for the surface modification of materials, due to a wide application to all materials; the possibility of getting a wide variety of structures with micro- and nano-scaled features; and a fast, repeatable and contactless process. Laser processing is unique method, which allows production of active surface with formation of the desired oxide, creation of nano/micro textures and change wettability of the surface. Due to excellent mechanical properties and moderate biocompatibility, Ti/Zr multi- layer thin films, as novel nanolayered composites were deposited by ion sputtering on Si substrate. Subsequently, the Ti/Zr thin films were irradiated by femtosecond laser pulses in air to induce the following modifications: (i) mixing of components within the thin film structures, (ii) formation of ultrathin oxide layer at the irradiated surfaces, and (iii) structuring of the surface arrays in form of ripple structure. The main focus of this experimental study was examined different surface motives with nano- and micrometre features. For this purpose, the modifications of Ti/Zr multilayers were included forma- tion of spots, lines and surfaces with different pulse energy, scanning speed i.e. number of pulses, z-distance. Laser-induced spots are composed of concentric circles, where the number of circles in individual spots is increased with increasing pulse energy. Maxi- mum depth in the centre of spots and total roughness are gradually rising with pulse energy, but heights between ablated layers in these spots does not match with the thick- ness of layers, but these deviations are not significant. Lines and surfaces were scanned with different scanning rate, the conditions for formation of well-defined LSFL (low spa- tial frequency LIPSS) are determined. The periodic structures at high scanning rate (3 mm/s) are mainly formed on the multilayer thin film. However, the degree of ablation becomes higher at the lowest rate (0.5 mm/s) where the ripples mostly are formed on the Si substrate.
PB  - Moscow : Lebedev Physical Institute
C3  - UltrafastLight-2018 : International Conference on Ultrafast Optical Science : Book of Abstracts
T1  - Modification of Ti/Zr multilayer by femtosecond laser pulses
SP  - 100
EP  - 100
UR  - https://hdl.handle.net/21.15107/rcub_vinar_12441
ER  - 

@conference{
author = "Gaković, Biljana M. and Petrović, S. and Peruško, Davor and Mimidis, A. and Kavatzikidou, E. and Stratakis, E.",
year = "2018",
abstract = "Femtosecond laser texturing holds promise for the surface modification of materials, due to a wide application to all materials; the possibility of getting a wide variety of structures with micro- and nano-scaled features; and a fast, repeatable and contactless process. Laser processing is unique method, which allows production of active surface with formation of the desired oxide, creation of nano/micro textures and change wettability of the surface. Due to excellent mechanical properties and moderate biocompatibility, Ti/Zr multi- layer thin films, as novel nanolayered composites were deposited by ion sputtering on Si substrate. Subsequently, the Ti/Zr thin films were irradiated by femtosecond laser pulses in air to induce the following modifications: (i) mixing of components within the thin film structures, (ii) formation of ultrathin oxide layer at the irradiated surfaces, and (iii) structuring of the surface arrays in form of ripple structure. The main focus of this experimental study was examined different surface motives with nano- and micrometre features. For this purpose, the modifications of Ti/Zr multilayers were included forma- tion of spots, lines and surfaces with different pulse energy, scanning speed i.e. number of pulses, z-distance. Laser-induced spots are composed of concentric circles, where the number of circles in individual spots is increased with increasing pulse energy. Maxi- mum depth in the centre of spots and total roughness are gradually rising with pulse energy, but heights between ablated layers in these spots does not match with the thick- ness of layers, but these deviations are not significant. Lines and surfaces were scanned with different scanning rate, the conditions for formation of well-defined LSFL (low spa- tial frequency LIPSS) are determined. The periodic structures at high scanning rate (3 mm/s) are mainly formed on the multilayer thin film. However, the degree of ablation becomes higher at the lowest rate (0.5 mm/s) where the ripples mostly are formed on the Si substrate.",
publisher = "Moscow : Lebedev Physical Institute",
journal = "UltrafastLight-2018 : International Conference on Ultrafast Optical Science : Book of Abstracts",
title = "Modification of Ti/Zr multilayer by femtosecond laser pulses",
pages = "100-100",
url = "https://hdl.handle.net/21.15107/rcub_vinar_12441"
}

Gaković, B. M., Petrović, S., Peruško, D., Mimidis, A., Kavatzikidou, E.,& Stratakis, E.. (2018). Modification of Ti/Zr multilayer by femtosecond laser pulses. in UltrafastLight-2018 : International Conference on Ultrafast Optical Science : Book of Abstracts
Moscow : Lebedev Physical Institute., 100-100.
https://hdl.handle.net/21.15107/rcub_vinar_12441

Gaković BM, Petrović S, Peruško D, Mimidis A, Kavatzikidou E, Stratakis E. Modification of Ti/Zr multilayer by femtosecond laser pulses. in UltrafastLight-2018 : International Conference on Ultrafast Optical Science : Book of Abstracts. 2018;:100-100.
https://hdl.handle.net/21.15107/rcub_vinar_12441 .

Gaković, Biljana M., Petrović, S., Peruško, Davor, Mimidis, A., Kavatzikidou, E., Stratakis, E., "Modification of Ti/Zr multilayer by femtosecond laser pulses" in UltrafastLight-2018 : International Conference on Ultrafast Optical Science : Book of Abstracts (2018):100-100,
https://hdl.handle.net/21.15107/rcub_vinar_12441 .

TY  - CONF
AU  - Pjević, Dejan J.
AU  - Peruško, Davor
AU  - Skoulas, E.
AU  - Stratakis, E.
AU  - Siketić, Z.
AU  - Bogdanović-Radović, Iva
AU  - Savić, Tatjana D.
AU  - Čomor, Mirjana
AU  - Petrović, S.
PY  - 2017
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10946
AB  - Modification of single titanium and complex titanium-aluminium samples by laser processing in the femtosecond time domain is unexplored field. This work included a study of the effects caused by changes in the composition and morphology of the compact Ti thin film and multilayer Ti/5x(Al/Ti) structure. Titanium and its oxides have specific physical, chemical and mechanical properties, such as high corrosion resistance, good stability, high strength and porosity. Titanium−oxide materials in different types and forms have shown great potential as ideal and powerful photocatalysts for various significant reactions due to their chemical stability, nontoxicity, and high reactivity. Laser surface modification allows production of active surface with formation of the desired oxide, creation of nano/micro textures and change wettability of the surface. The samples were processed by focused an Yb:KGW laser beam with 1026 nm central wavelength, 170 fs pulse duration and repetition rate of 1 kHz. The laser-induced morphological and composition modifications have shown dependence on applied intensities and number of laser pulses. The formed surface nanostructures on the Ti and Ti/Al thin film surface (5x5 mm) are obtained in scanning regime. The results show an increase in surface roughness, formation of parallel periodic surface structures, appearance of hydrodynamic features and ablation of surface material. At low pulse energies range (not over 0.01 mJ) and effective 50 pulses, the two types of LIPSS can be observed: low and high spatial frequency LIPSS (HSFL and LSFL). The low spatial frequency LIPSS (LSFL), oriented perpendicular to the laser polarization with periods slightly lower than the irradiation wavelength, was typically formed. The laser-induced surface oxidation was analysed by Elastic Recoil Detection Analysis (ERDA) in the subsurface part of the investigated samples, which indicates formation Ti-oxide and mixture of Al- and Ti-oxide in the case of multilayer structure. Photocatalytic degradation rate on the laser irradiated surface of Ti and Ti/Al thin films was compared with unmodified samples. The rate of photo-degradation was associated with changes in structure of Ti-oxide and in increasing of surface roughness with formation of periodic structure.
PB  - Belgrade : Institute of Physics Belgrade
C3  - PHOTONICA2017 : 6th International School and Conference on Photonics and COST actions: MP1406 and MP1402 : Program and the book of abstracts
T1  - Laser-induced periodic structure on Ti and Ti/Al thin films for photocatalytic application
SP  - 177
UR  - https://hdl.handle.net/21.15107/rcub_vinar_10946
ER  - 

@conference{
author = "Pjević, Dejan J. and Peruško, Davor and Skoulas, E. and Stratakis, E. and Siketić, Z. and Bogdanović-Radović, Iva and Savić, Tatjana D. and Čomor, Mirjana and Petrović, S.",
year = "2017",
abstract = "Modification of single titanium and complex titanium-aluminium samples by laser processing in the femtosecond time domain is unexplored field. This work included a study of the effects caused by changes in the composition and morphology of the compact Ti thin film and multilayer Ti/5x(Al/Ti) structure. Titanium and its oxides have specific physical, chemical and mechanical properties, such as high corrosion resistance, good stability, high strength and porosity. Titanium−oxide materials in different types and forms have shown great potential as ideal and powerful photocatalysts for various significant reactions due to their chemical stability, nontoxicity, and high reactivity. Laser surface modification allows production of active surface with formation of the desired oxide, creation of nano/micro textures and change wettability of the surface. The samples were processed by focused an Yb:KGW laser beam with 1026 nm central wavelength, 170 fs pulse duration and repetition rate of 1 kHz. The laser-induced morphological and composition modifications have shown dependence on applied intensities and number of laser pulses. The formed surface nanostructures on the Ti and Ti/Al thin film surface (5x5 mm) are obtained in scanning regime. The results show an increase in surface roughness, formation of parallel periodic surface structures, appearance of hydrodynamic features and ablation of surface material. At low pulse energies range (not over 0.01 mJ) and effective 50 pulses, the two types of LIPSS can be observed: low and high spatial frequency LIPSS (HSFL and LSFL). The low spatial frequency LIPSS (LSFL), oriented perpendicular to the laser polarization with periods slightly lower than the irradiation wavelength, was typically formed. The laser-induced surface oxidation was analysed by Elastic Recoil Detection Analysis (ERDA) in the subsurface part of the investigated samples, which indicates formation Ti-oxide and mixture of Al- and Ti-oxide in the case of multilayer structure. Photocatalytic degradation rate on the laser irradiated surface of Ti and Ti/Al thin films was compared with unmodified samples. The rate of photo-degradation was associated with changes in structure of Ti-oxide and in increasing of surface roughness with formation of periodic structure.",
publisher = "Belgrade : Institute of Physics Belgrade",
journal = "PHOTONICA2017 : 6th International School and Conference on Photonics and COST actions: MP1406 and MP1402 : Program and the book of abstracts",
title = "Laser-induced periodic structure on Ti and Ti/Al thin films for photocatalytic application",
pages = "177",
url = "https://hdl.handle.net/21.15107/rcub_vinar_10946"
}

Pjević, D. J., Peruško, D., Skoulas, E., Stratakis, E., Siketić, Z., Bogdanović-Radović, I., Savić, T. D., Čomor, M.,& Petrović, S.. (2017). Laser-induced periodic structure on Ti and Ti/Al thin films for photocatalytic application. in PHOTONICA2017 : 6th International School and Conference on Photonics and COST actions: MP1406 and MP1402 : Program and the book of abstracts
Belgrade : Institute of Physics Belgrade., 177.
https://hdl.handle.net/21.15107/rcub_vinar_10946

Pjević DJ, Peruško D, Skoulas E, Stratakis E, Siketić Z, Bogdanović-Radović I, Savić TD, Čomor M, Petrović S. Laser-induced periodic structure on Ti and Ti/Al thin films for photocatalytic application. in PHOTONICA2017 : 6th International School and Conference on Photonics and COST actions: MP1406 and MP1402 : Program and the book of abstracts. 2017;:177.
https://hdl.handle.net/21.15107/rcub_vinar_10946 .

Pjević, Dejan J., Peruško, Davor, Skoulas, E., Stratakis, E., Siketić, Z., Bogdanović-Radović, Iva, Savić, Tatjana D., Čomor, Mirjana, Petrović, S., "Laser-induced periodic structure on Ti and Ti/Al thin films for photocatalytic application" in PHOTONICA2017 : 6th International School and Conference on Photonics and COST actions: MP1406 and MP1402 : Program and the book of abstracts (2017):177,
https://hdl.handle.net/21.15107/rcub_vinar_10946 .