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Yearbook 2010 LGP2 102 Olivier Pras +33 476 826 974 [email protected] Supervisors : Pr.D.Chaussy, Dr.D.Beneventi About 40 years ago, semiconductor industry grew with materials like silicon. For few years this same industry is interested in organic materials: the conductor polymers. These polymers can used for organic light emitting diode (OLED), organic thin film transistor (OTFT) or RFID antenna …. The main advantage is the easy manufacturing. Indeed some soluble polymers exist, which permits the use of some printing processes for the depositing of the polymer layer and the elaboration of electronic devices. Printing processes are technologies which are often used for the creation of a pattern and particularly inkjet printing.[1] In this context we focus our studies on the formulation of functional inks. Many different approaches are used for the generation of nanoparticles in order to obtain the required properties (photoluminescence, electroluminescence, conductivity) like the sol-gel process or the microemulsion method. Another way (miniemulsion) is specially formulated heterophase systems in which stable nanodroplets of one phase are dispersed in a second, continuous phase. Because each of the nanodroplets can be regarded as a nanoscopic, individual batch reactor, a whole variety of reactions and processes resulting in both organic and inorganic nanoparticles can be performed. [2] To create a stable emulsion of very small droplets the droplets must be stabilized against molecular diffusion degradation (Ostwald ripening[3]) and against coalescence by collisions. Stabilization of emulsions against coalescence can be obtained by the addition of appropriate surfactants, which provide either electrostatic or steric stabilization to the droplets. Once all these degradations blocked, small stable droplets ranging in size between 30 and 500 nm are formed. Study of polymers miniemulsification: Surface functionalization by printing process year Introduction Background Printing processes 2 nd
Transcript of Yerabook 2010 fullcerig.pagora.grenoble-inp.fr/dossier/LGP2-yearbook...Yearbook 2010 FV...
Yearbook 2010 LGP2102
Olivier Pras+33 476 826 [email protected] : Pr.D.Chaussy, Dr.D.Beneventi
About 40 years ago, semiconductor industry grew withmaterials like silicon. For few years this same industry is
interested in organic materials: the conductor polymers. These polymerscan used for organic light emitting diode (OLED), organic thin film transistor(OTFT) or RFID antenna …. The main advantage is the easymanufacturing. Indeed some soluble polymers exist, which permits the useof some printing processes for the depositing of the polymer layer and theelaboration of electronic devices. Printing processes are technologies whichare often used for the creation of a pattern and particularly inkjet printing.[1]
In this context we focus our studies on the formulation offunctional inks. Many different approaches are used for
the generation of nanoparticles in order to obtain the required properties(photoluminescence, electroluminescence, conductivity) like the sol-gelprocess or the microemulsion method. Another way (miniemulsion) isspecially formulated heterophase systems in which stable nanodroplets ofone phase are dispersed in a second, continuous phase. Because each ofthe nanodroplets can be regarded as a nanoscopic, individual batch reactor,a whole variety of reactions and processes resulting in both organic andinorganic nanoparticles can be performed. [2] To create a stable emulsionof very small droplets the droplets must be stabilized against moleculardiffusion degradation (Ostwald ripening[3]) and against coalescence bycollisions. Stabilization of emulsions against coalescence can be obtainedby the addition of appropriate surfactants, which provide either electrostaticor steric stabilization to the droplets. Once all these degradations blocked,small stable droplets ranging in size between 30 and 500 nm are formed.
Study of polymersminiemulsification: Surfacefunctionalization by printing process
year
Introduction
Background
Printing processes
2nd
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A derived polymer from cellulose is used: cellulose acetate
butyrate with an average Mn of 70,000 (Aldrich). Next, the polymer isminiemulsified with a cationic surfactant (Hexadecyltrimethylammoniumbromide : HTAB). A colloidal aqueous suspension is obtained with a meandiameter of 68 nm. (Figure 1).
The influenceof a cationic
(Hexadecyltrimethylammonium bromide : HTAB) and an anionic (Sodiumdodecyl sulfate : SDS) surfactants are studied along with the concentrationinfluence.By variation of the relative amount of the surfactant, it is possible to vary the
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Resultsa.Miniemulsification of cellulose actetate butyrate(CAB)
Figure 1 : Structure of CAB (a) ; Particle size distribution of the CAB dispersion (b)
b.Type of surfactant and influence of concentration.
Figure 2 : Particle size of CAB versus surfactant concentration of HTAB (a) and SDS (b)
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Yearbook 2010 LGP2104
particle size over a wide range. Figure 2 shows that, depending on thetype of the surfactant, different size ranges can be achieved.
An orange 2,7-poly(9,9-dialkylfluorene-co-fluorenone)
(PFFO) is synthesized by Nickel(0) coupling (Yamamoto route) of thecorresponding dibromo-monomers to obtain an efficient yellowishphotoluminescence [4]. Then, this synthesized polymer is miniemulsifiedwith cationic surfactant such as hexadecyltrimethylammonium bromide(HTAB) giving stable aqueous suspensions of yellowish cationic colloidalparticles with a mean diameter of 45 nm and a zeta potential of + 68mV. Figure 3 shows three measurements of fluorescence spectroscopyrealized on the polymer: as solid state, as soluble in chloroform and asparticle in miniemulsion. The PFFO as solid state has a peak near 540nm while the PFFO soluble in chloroform peak is for 420 nm. The PFFOin miniemulsion has the two peaks at 420 and 540 nm.
[1] B.D. de Gans, P. Duineveld, et U. Schubert, “Inkjet Printing ofPolymers: State of the Art and Future Developments,” AdvancedMaterials, vol. 16, 2004, pp. 203-213.
[2] K. Landfester, “Synthesis of Colloidal Particles in Miniemulsions,”
References
Olivier Pras
c.A photoluminescent polymer
Figure 3 : Structure of PFFO (a) ; Emission Spectra of PFFO as solid state, liquid state andparticle (b)
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Annual Review of Materials Research, vol. 36, 2006, pp. 231-279.
[3] A.S. Kabalnov, “Can Micelles Mediate a Mass Transfer between OilDroplets?,” Langmuir, vol. 10, Mar. 1994, pp. 680-684.
[4] S. Panozzo, J. Vial, Y. Kervella, et O. Stephan, “Fluorene-fluorenonecopolymer: Stable and efficient yellow-emitting material forelectroluminescent devices,” Journal of Applied Physics, vol. 92, Oct. 2002,pp. 3495-3502.
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Papermaking and
Converting Biomaterials
Packaging
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