Self Assembled Structures

Defect pattern self-assembly and guided nanoparticle (NP) assembly in thin liquid crystal films

A limiting factor for the development and application of nanotechnology is the difficulty of aligning and spatially organize functional nanoparticles over large length scales. The classical top-down approach allows to create ordered structures and templates using micro- and nano-fabrication techniques such as ion beam lithography. We propose a bottom-up approach to create patterns and templates by dispersing or conjugating functional NP with an anisotropic LC materials that can self-assemble into ordered and aligned structures over multiple length scales. Periodic patterns of topological defects can be created in thin films of layered materials such as smectic LC and cholesteric LC. The interaction of NPs with the core of the defects determines both a regular spatial distribution and alignment of NPs.

The dispersion of gold nanoparticles (Au NP) in a chiral nematic LC evidence the insurgence of an order change in the LC host. Moreover, a comparative analysis based on dielectric and voltammetric spectroscopies performed on pure LC and on Au NP-doped LC shows that Au NP’s presence besides affecting LC order influences its electric properties: ion conductivity results importantly reduced, and beyond a threshold value of the applied field electrophoresis phenomena are induced.

Another activity deals with the studies on the transport and the organization of NP on scales ranging from microns to centimeters by means of topological defects in LC. These defects are generated and modified by means of the holographic control of the command surfaces (polarization sensitive dye films are used on glass substrates to record polarization holograms ) which confine the LC. The quantum dots dispersed in the medium accumulate in the topological defects and their position can be tuned by laser light.

The results obtained from these experiments expand the prospects for the development of miniaturized devices for the optics, photonics and microfluidics.

Molecular architectures at interfaces

The interfaces between bulk media are often site of reactions and phenomena which are distinct from the bulk substances and frequently dominate the macroscopic properties of the entire system. Understanding how molecules adsorb and react with these surfaces attract interests because of  several potential applications in industrial processes and everyday life. Catalyses, combustions, lubrification, adhesion, wetting, electrochemical reactions are only few examples of phenomena of industrial interest which are governed by interfacial properties. Polymer surfaces and interfaces play an increasingly important role in modern electronic and optoelectronic technologies (i.e. organic transistors, OLED), as well as in biomedical applications (i.e., biocompatibility).

The challenging aspects of this surface work are always sensitivity and specificity, i.e. detecting molecularly thin surface layer (below 1015 molecules/cm2), distinguish its properties from the bulk substance ones.

To address this problem, surface-specific analytical technique with monolayer sensitivity has been recently developed successfully applied to various kinds of surfaces and interfaces. IR and visible sum-frequency generation (SFG) vibrational spectroscopy is a powerful and versatile in situ surface probe which permits identification of surface molecular species and provides information about orientation of functional groups at the surface. SFG is non destructive, highly sensitive, and has good spatial, temporal, and spectral resolution. Because the technique works in real time under water and protein solutions (and, theoretically, under blood) it is very well suited for studying biomaterials.

Recently SFG has been demonstrated as novel spectroscopic tool for molecular chirality, with significantly better sensitivity of Circular Dichroism, which allowed chiral vibrational spectra from a molecular monolayer. As a second-order nonlinear optical technique, SFG is symmetry forbidden in centrosymmetric bulk under the electric-dipole approximation , but allowed at interfaces where inversion symmetry is naturally broken. By choosing different input/output polarization combination, information on the orientation of selected atomic groups at sub-molecular level, as well as molecular configuration can be achieved.

Molecular architectures at interfaces

Facilities & Labs

Synchrotron and laboratory source of x-ray scattering

AFM

Polarizing optical microscopy and confocal microscopy

Voltammetry

SFG

Langmuir trough

People

Aprile

Cipparone

Federica_ciuchiFederica

Ciuchi

Giuseppe-StrangiGiuseppe

Strangi

Alfredo_MazzullaAlfredo

Mazzulla

Pasquale_PagliusiPasquale

Pagliusi

michel giocondoMichele

Giocondo

Roberto_bartolinoRoberto

Bartolino

Bruno_ZapponeBruno

Zappone

Publications

  1. Coursault, J.-F. Blach, J. Grand, A. Coati, A. Vlad, B. Zappone, D. Babonneau, G. Levi, N. Félidj, B. Donnio, J.-L. Gallani, M. Alba, Y. Garreau, Y. Borensztein, M. Goldmann, and E. Lacaze “Tailoring Anisotropic Interactions between Soft Nanospheres Using Dense Arrays of Smectic Liquid Crystal Edge Dislocations” ACS Nano (2015).
  2. Coursault, D.; Zappone, B.; Coati, A.; Boulaoued, A.; Pelliser, L.; Limagne, D.; Boudet, N.; Haj Ibrahim, B.; de Martino, A.; Alba, M.; Goldmann, M.; Garreau, Y., Gallas, B.; Lacaze, E. “Self-organized arrays of dislocations in thin smectic liquid crystal films” Soft Matter (2016) DOI: 10.1039/C5SM02241J.
  3. Gryn, E. Lacaze, R. Bartolino, B. Zappone “Controlling the self-assembly of periodic defect patterns in smectic liquid crystal films with electric fields”, Advanced Functional Materials 25 (2014) 142-149.
  4. Coursault, B. H. Ibrahim, L. Pelliser, B. Zappone, A. de Martino, E. Lacaze and B. Gallas “Modeling the optical properties of self-organized thin films of 8CB molecules” Optics Letters 22 (2014) 23182–23191.
  5. Coursault, J. Grand, B. Zappone, H. Ayeb, G. Lévi, N. Félidj and E. Lacaze, “Linear self-assembly of nanoparticles within liquid crystal defect arrays”, Advanced Materials 24 (2012) 1461–1465.
  6. Zappone, C. Meyer, L. Bruno and E. Lacaze, “Periodic lattices of frustrated focal conic defect domains in smectic liquid crystal films”, Soft Matter, 8 (2012), 4318 – 4326.
  7. Zappone, E. Lacaze, H. Ayeb, M. Goldmann, P. Barois, M. Alba: “Self-ordered arrays of linear defects and virtual singularities in thin smectic-A films”, ‘Hot Article’ in Soft Matter 7 (2010) 1161 – 1167.
  8. Zappone, E. Lacaze: “Surface-frustrated periodic textures of smectic-A liquid crystals on crystalline surfaces”, Physical Review E, 78 (2008) 061704.
  9. Gary, R., Carbone, G., Petriashvili, G., De Santo, M.P., Barberi, R. Liq.Cryst. Vol. 43, Issue 2, 2016, pp 216-221
  10. Effects of gold nanoparticle dispersion in a chiral liquid crystal matrix Infusino, M, De Luca, A., Ciuchi, F, Ionescu, A., Scaramuzza, N., Strangi, G. 2013 Molecular Crystals and Liquid Crystals 572 (1), pp. 59-65
  11. Optical and electrical characterization of a gold nanoparticle dispersion in a chiral liquid crystal matrix Infusino M., De Luca A., Ciuchi F., Ionescu A., Scaramuzza N., Strangi G. J.of Mat.Sci. Vol. 49, Issue 4, 2014, pp1805-1811
  12. Light manipulation of nanoparticles in arrays of topological defects Kasyanyuk D., Pagliusi P., Mazzulla A., Reshetnyak V., Reznikov Y., Provenzano C., Giocondo M., Vasnetsov M., Yaroshchuk O., Cipparrone G. 2016 Scientific Reports 6, 20742
  13. Aprile, P. Pagliusi, F. Ciuchi, R. Pinalli and E. Dalcanale “Probing cavitand-organosilane hybrid bilayers via sum frequency vibrational spectroscopy” Langmuir 30, 12843 (2014)
  14. C.Y. Chen, Wei-Tao Liu, P. Pagliusi and Y.R. Shen “Sum-frequency vibrational spectroscopy study of photo-irradiated polymer surfaces” Macromolecules 42, 2122-2126 (2009)
  15. P. Pagliusi, F. Lagugné-Labarthet, D.K. Shenoy, E. Dalcanale and Y.R. Shen “Sensing vase-to-Kite switching of cavitands by Sum-Frequency Vibrational Spectroscopy” Journal of the American Chemical Society 128, 12610-12611 (2006)
  16. P. Pagliusi, C.Y. Chen and Y.R. Shen, “Molecular orientation and alignment of rubbed poly(vinyl cinnamate) surfaces” Journal of Chemical Physics 125, 201104 (2006)

Patents

Project

Latest News

  • Loretta del Mercato, si aggiudica l’ERC STARTING GRANT 2017

    Loretta del Mercato, si aggiudica  l’ERC STARTING GRANT 2017

    uno dei bandi più competitivi a livello europeo.

    Lecce, 6 settembre 2017 

    Lo European Research Council, che promuove la ricerca di eccellenza in Europa, nei giorni scorsi ha reso noti i nomi dei 406 vincitori della selezione ERC STARTING GRANT 2017, il bando tra i più competitivi a livello internazionale.

    (more…)
  • Zeiss Microscopy Technology and Complete Correlative Workflow

    Zeiss Microscopy Technology and Complete Correlative Workflow

    Lecce, Italy, 2017 Wednesday July 19th 

    CNR NANOTEC @ Lecce, Aula Seminari – pal. G, Piano Terra

    Program – PDF

    Zeiss, as microscopy technology leader, provides the unique complete imaging solution ranging from light, confocal, electron, ion and Xray modalities with a complete and straightforward correlative workflow. An overview of different technologies will be presented with a special focus on X-Rray microscopy.

  • MCS 2017

    International Workshop on Micropropulsion and CubeSats

    Bari, Italy, 26 – 27 June 2017

    Program – MSC2017

    This narrow-field, invited-only meeting is the first attempt to bring together the Materials and Micropropulsion communities with a view to contribute to the development of the Global Materials and Micropropulsion Roadmap, and set such meetings to a regular basis.

Job Openings