Quantitative Nanomechanical Properties of Multilayer Films Made of Polysaccharides through Spray Assisted Layer-by-Layer Assembly.

Nanomechanical properties of alginate/chitosan (Alg/Chi) multilayer films, obtained through spray assisted layer-by-layer assembly, were studied by means of PeakForce quantitative nanomechanical mapping atomic force microscopy (PF-QNM AFM). Prepared at two different alginate concentrations (1.0 and 2.5 mg/mL) and a fixed chitosan concentration (1.0 mg/mL), Alg/Chi films have an exponential growth in thickness with a transition to a linear growth toward a plateau by increasing the number of deposited bilayers. Height, elastic modulus, deformation, and adhesion maps were simultaneously recorded depending on the number of deposited bilayers. The elastic modulus of Alg/Chi films was found to be related to the mechanism of growth in contrast to the adhesion and deformation. A comparison of the nanomechanical properties obtained for non-cross-linked and thermally cross-linked Alg/Chi films revealed an increase of the elastic modulus after cross-linking regardless alginate concentration. The incorporation of iron oxide nanoparticles (NPs), during the spray preparation of the films, gave rise to nanocomposite Alg/Chi films with increased elastic moduli with the number of incorporated NPs layers. Deformation maps of the films strongly suggested the presence of empty spaces associated with the method of preparation. Finally, adhesion measurements point out to a significant role of NPs on the increase of the adhesion values found for nanocomposite films.journal article2017 01 092016 12 15importe

Laser Fabrication of Polymer Ferroelectric Nanostructures for Nonvolatile Organic Memory Devices

8 pags.; 5 figs.© 2015 American Chemical Society. Polymer ferroelectric laser-induced periodic surface structures (LIPSS) have been prepared on ferroelectric thin films of a poly(vinylidene fluoride-trifluoroethylene) copolymer. Although this copolymer does not absorb light at the laser wavelength, LIPSS on the copolymer can be obtained by forming a bilayer with other light-absorbing polymers. The ferroelectric nature of the structured bilayer was proven by piezoresponse force microscopy measurements. Ferroelectric hysteresis was found on both the bilayer and the laser-structured bilayer. We show that it is possible to write ferroelectric information at the nanoscale. The laser-structured ferroelectric bilayer showed an increase in the information storage density of an order of magnitude, in comparison to the original bilayer.The authors gratefully acknowledge the financial support of the Spanish Ministry of Economy and Competitiveness (MINECO), through Contract Nos. MAT 2011-23455, MAT 2012- 33517, and CTQ 2013-43086-P. D.E.M. thanks CSIC for the tenure of JAE-Pre fellowship and Fondo Social Europeo (FSE) for cofinancing the JAE Program. A.R.R. and E.R. thank MINECO for the tenure of a FPI contract (BES-2013-062620) and a Ramón y Cajal contract (No. RYC-2011-08069), respectively.Peer Reviewe

Laterally-resolved mechanical and tribological properties of laser-structured polymer nanocomposites

[EN]In this work, we report on a detailed quantitative nanomechanical mapping of free-standing films of poly(ethylene terephthalate) (PET) and the composite PET/expanded graphite (EG) with 0.4% in weight of the nanoadditive, and of these materials nanostructured by laser irradiation. By using atomic force microscopy, we obtained simultaneously the topography, surface elastic modulus and adhesion force maps of the materials. Young's modulus images exhibited higher values for the composite in comparison to those of the neat polymer and for the nanostructured films in contrast to the non-nanostructured ones. Additionally, we explored the tribological properties of these systems at the nanoscale. Using lateral force microscopy, we observed a decrease in the friction coefficient for the nanocomposite as compared to the neat polymer, while quantifying an increase for both laser-structured samples. Our results are discussed taking into consideration the possible changes that the samples might undergo during processing, as well as the changes imposed by the complex geometry of the nanometric features in these laterally-resolved mechanical measurements

Shaping polymer surfaces by laser interactions: formation and nanomechanical properties of LIPSS in controlled enviroments

TNT2019 edition will take place in San Sebastian, Spain, Sept. 30 - Oct. 4, 2019. --http://tntconf.org/2019/index.php?conf=1

Impact of environmental conditions on the formation and physicochemical properties of laser-structured polymer surfaces

Spring Meeting of the European Materials Research Society (E-MRS) to be held as a VIRTUAL Conference from May 31st to June 3rd, 2021. .- https://www.european-mrs.com/meetings/2021-spring-meeting-

Wrinkling poly(trimethylene 2,5-furanoate) free-standing films: Nanostructure formation and physical properties

Polymer nanostructures were developed on fully bio-based poly(trimethylene furanoate) (PTF) films, by using the technique of Laser Induced Periodic Surface Structures (LIPSS). We found that irradiation times between 1 and 8 min allowed the formation of periodic and nanometric ripples, when using an UV pulsed laser source at a fluence of 8 mJ/cm2. The wrinkled surfaces were studied by a combined macro- and nanoscale approach. We evaluated possible physicochemical changes taking place on the polymer surface after irradiation by infrared spectroscopy, contact angle measurements and atomic force microscopy. The macroscopic properties of PTF showed almost no changes after nanostructure formation, differently from the results previously found for the terephthalic counterparts, as poly(ethylene terephthalate), PET, and poly(trimethylene terephthalate), PTT. At the nanoscale, the surface mechanical properties of the nanostructured PTF were found to be improved, as evidenced by force spectroscopy measurements. In particular, stiffer surfaces characterized by an increased Young's modulus were measured for the nanostructured sample.This work has been supported by Ministry of Science, Innovation and Universities (MCIU, Spain) under the project CTQ2016-75880-P. D.E.M. acknowledges the financial support obtained through the Post-Doctoral fellowship “Juan de la Cierva – Incorporación” (IJCI-2017-31600, MCIU, Spain). E.R. thanks MCIU for the tenure of a Ramón y Cajal contract (No. RYC-2011-08069).Peer reviewe

Nanosecond laser induced patterning of silicon surfaces

20th International Vacuum Congress, Korea 21-26 Agoust 2016 ; www.ivc20.com/Peer Reviewe

Local mechanical properties of nanostructured polymer surfaces

2021 Spring Meeting of the European Materials Research Society (E-MRS) to be held as a VIRTUAL Conference from May 31st to June 3rd, 2021. (The VIRTUAL 2021 Spring Meeting will consist of parallel symposia with invited speakers, oral and poster presentations, assorted by plenary sessions and a number of workshops and training courses.) .-https://www.european-mrs.com/meetings/2021-spring-meeting-

Crystallization and phase separation in PEDOT:PSS/PEO blend thin films: Influence on mechanical and electrical properties at the nanoscale

Thin films of polymeric blends composed of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and polyethylene oxide (PEO) were investigated by varying the concentration of the two components over the entire range of compositions and the molecular weight of PEO. Phase separation and crystallization have been studied at different length scales by combining Atomic Force Microscopy (AFM) and Grazing Incidence Wide Angle X-ray Scattering (GIWAXS) using synchrotron light. Several different arrangements in the thin films of the two polymers constituting the blend were observed and discussed in detail, providing information about their reciprocal influence at the micro- and nano-scale. In addition to that, we were able to estimate quantitative nanomechanical and nanoelectrical properties via AFM and finally revealing the dependence of the thin films' physical properties on their composition and structure. By varying the blend composition, we achieved different coating capability, mechanical properties, and electrical conductivity. Furthermore, depending on the PEO molecular weight, the electrical response of the resulting blends’ thin films shows some differences. In the low range concentration, the blend thin films with high molecular weight PEO present coarser conducting paths than in those with the low molecular weight counterparts. For intermediate concentrations, a more effective phase segregation of PEDOT:PSS and PEO is achieved for high molecular weight PEO. These differences are also translated to different electrical conductivity.We acknowledge funding from the Spanish State Research Agency (AEI) through projects PID2019-107514 GB-I00/AEI/10.13039/501100011033 and PID2019-106125 GB-I00/AEI/10.13039/501100011033. We also acknowledge funding from Eusko Jaurlaritza (Basque Government) through the Grants IT-1566-22.Peer reviewe

Nanosecond laser-induced grating formation in silicon

COLA 2017, Marseille (France) from 3 to 8 september 2017. -- https://cola2017.sciencesconf.org/Peer Reviewe