Staff directory Alejandro Fernández Muñoz

Alejandro Fernández Muñoz

Fellowship Master Student
alejandro.fernandez(ELIMINAR)@icn2.cat
Atomic Manipulation and Spectroscopy

Publications

2018

  • Design of a Multifunctional Nanoengineered PLLA Surface by Maximizing the Synergies between Biochemical and Surface Design Bactericidal Effects

    Nerantzaki M., Kehagias N., Francone A., Fernández A., Sotomayor Torres C.M., Papi R., Choli-Papadopoulou T., Bikiaris D.N. ACS Omega; 3 (2): 1509 - 1521. 2018. 10.1021/acsomega.7b01756. IF: 0.000

    Nanotechnology, the manipulation of matter on atomic, molecular, and supramolecular scales, has become the most appealing strategy for biomedical applications and is of great interest as an approach to preventing microbial risks. In this study, we utilize the antimicrobial performance and the drug-loading ability of novel nanoparticles based on silicon oxide and strontium-substituted hydroxyapatite to develop nanocomposite antimicrobial films based on a poly(l-lactic acid) (PLLA) polymer. We also demonstrate that nanoimprint lithography (NIL), a process adaptable to industrial application, is a feasible fabrication technique to modify the surface of PLLA, to alter its physical properties, and to utilize it for antibacterial applications. Various nanocomposite PLLA films with nanosized (black silicon) and three-dimensional (hierarchical) hybrid domains were fabricated by thermal NIL, and their bactericidal activity against Escherichia coli and Staphylococcus aureus was assessed. Our findings demonstrate that besides hydrophobicity the nanoparticle antibiotic delivery and the surface roughness are essential factors that affect the biofilm formation. © 2018 American Chemical Society.


  • Fabrication and replication of re-entrant structures by nanoimprint lithography methods

    Kehagias N., Francone A., Guttmann M., Winkler F., Fernández A., Torres C.M.S. Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics; 36 (6, 06JF01) 2018. 10.1116/1.5048241. IF: 1.314

    In this work, the authors present and demonstrate a simple method to fabricate and mass replicate re-entrant structures. The method consists of the direct imprinting of polymer mushroomlike microstructures produced by a combination of photolithography and nickel up-plating process. In particular, they have studied the conditions to generate highly robust mushroomlike topographies and their topographical impact on the replication process. They discuss all the imprinting conditions suitable to replicate such topographies using both ultraviolet light assisted nanoimprint lithography (UV-NIL) and thermal NIL methods in two polymer films, poly(methyl methacrylate) and polypropylene, and a hybrid (organic-inorganic) UV light curable photoresist, namely, Ormocomp. Re-entrant topographies have been widely studied for liquid/oil repelling and dry adhesive properties, whereas in their experiments, they have proved evidence for their amphiphobic potential. © 2018 Author(s).


2017

  • Design of Hierarchical Surfaces for Tuning Wetting Characteristics

    Fernández A., Francone A., Thamdrup L.H., Johansson A., Bilenberg B., Nielsen T., Guttmann M., Sotomayor Torres C.M., Kehagias N. ACS Applied Materials and Interfaces; 9 (8): 7701 - 7709. 2017. 10.1021/acsami.6b13615. IF: 7.504

    Patterned surfaces with tunable wetting properties are described. A hybrid hierarchical surface realized by combining two different materials exhibits different wetting states, depending on the speed of impingement of the water droplets. Both "lotus" (high contact angle and low adhesion) and "petal" (high contact angle and high adhesion) states were observed on the same surface without the need of any modification of the surface. The great difference between the capillary pressures exerted by the microstructures and nanostructures was the key factor that allowed us to tailor effectively the adhesiveness of the water droplets. Having a low capillary pressure for the microstructures and a high capillary pressure for the nanostructures, we allow to the surface the possibility of being in a lotus state or in a petal state. © 2017 American Chemical Society.


  • Hierarchical surfaces for enhanced self-cleaning applications

    Fernández A., Francone A., Thamdrup L.H., Johansson A., Bilenberg B., Nielsen T., Guttmann M., Sotomayor Torres C.M., Kehagias N. Journal of Micromechanics and Microengineering; 27 (4, 045020) 2017. 10.1088/1361-6439/aa62bb. IF: 1.794

    In this study we present a flexible and adaptable fabrication method to create complex hierarchical structures over inherently hydrophobic resist materials. We have tested these surfaces for their superhydrophobic behaviour and successfully verified their self-cleaning properties. The followed approach allow us to design and produce superhydrophobic surfaces in a reproducible manner. We have analysed different combination of hierarchical micro-nanostructures for their application to self-cleaning surfaces. A static contact angle value of 170 with a hysteresis of 4 was achieved without the need of any additional chemical treatment on the fabricated hierarchical structures. Dynamic effects were analysed on these surfaces, obtaining a remarkable self-cleaning effect as well as a good robustness over impacting droplets. © 2017 IOP Publishing Ltd.


2015

  • Residual layer-free Reverse Nanoimprint Lithography on silicon and metal-coated substrates

    Fernández A., Medina J., Benkel C., Guttmann M., Bilenberg B., Thamdrup L.H., Nielsen T., Sotomayor Torres C.M., Kehagias N. Microelectronic Engineering; 141: 56 - 61. 2015. 10.1016/j.mee.2014.11.025. IF: 1.197

    In this work we demonstrate that Reverse Nanoimprint Lithography is a feasible and flexible lithography technique applicable to the transfer of micro and nano polymer structures with no residual layer over areas of cm2 areas on silicon, metal and non-planar substrates. We used a flexible polydimethylsiloxane stamp with hydrophobic features. We present residual layer-free patterns imprinted using a commercial poly(methylmethacrylate) thermoplastic polymer over silicon, nickel and pre-patterned substrates. Our versatile patterning technology is adaptable to free form nano structuring and has coupling to adhesion technologies. © 2014 Elsevier B.V. All rights reserved.