Cellulose Nanocrystals: Size Characterization and Controlled Deposition by Inkjet Printing

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dc.contributor.authorNavarro, Fernandoen
dc.contributor.committeechairRoman, Marenen
dc.contributor.committeememberEsker, Alan R.en
dc.contributor.committeememberDavis, Richey M.en
dc.contributor.committeememberRenneckar, Scott H.en
dc.contributor.committeememberRojas, Orlando J.en
dc.contributor.departmentMacromolecular Science and Engineeringen
dc.date.accessioned2014-03-14T20:14:08Zen
dc.date.adate2010-08-19en
dc.date.available2014-03-14T20:14:08Zen
dc.date.issued2010-06-29en
dc.date.rdate2013-08-22en
dc.date.sdate2010-07-19en
dc.description.abstractInkjet printing has generated considerable interest as a technique for the patterning of functional materials in the liquid phase onto a substrate. Despite its high promise, the phenomena associated with inkjet printing remain incompletely understood. This research project investigates inkjet printing of cellulose nanocrystals (CNCs) as a possible method for the fabrication of cellulose micropatterns. CNCs were prepared from wood pulp by H₂SO₄ hydrolysis and characterized in terms of length, width, and thickness distributions by atomic force microscopy (AFM) and dynamic light scattering. Aqueous CNC suspensions were characterized in terms of shear viscosity with a rheometer. Glass substrates were cleaned with a detergent solution, aqua regia, or a solvent mixture, and characterized in terms of surface chemical composition, surface free energy, polarity, roughness, ζ-potential, and surface charge distribution in air by X-ray photoelectron spectroscopy, contact angle measurements, AFM, streaming potential, and scanning Kelvin probe microscopy (SKPM). Additionally, poly(ethylene glycol)-grafted glass substrates were prepared and characterized in terms of surface free energy, polarity, and roughness. Aqueous CNC suspensions were printed in different patterns onto the different glass substrates with a commercial, piezoelectric drop-on-demand inkjet printer. Inkjet deposited droplet residues and micropatterns were analyzed by AFM, scanning electron microscopy, and polarized-light microscopy. At low CNC concentrations (0.05 wt %), inkjet-deposited droplets formed ring-like residues due to the "coffee drop effect". The "coffee drop effect" could be suppressed by the use of higher CNC concentrations. The resulting dot-like droplet residues exhibited Maltese cross interference patterns between crossed polarizers, indicating a radial orientation of the birefringent, elongated CNCs in these residues. The observed Maltese cross interference patterns represent unprecedented indirect evidence for a center-to-edge radial flow in drying droplets. The degree of definition of the micropatterns depended strongly on the surface properties of the glass substrates. Well-defined micropatterns were obtained on aqua regia-cleaned substrates. In addition to the surface free energy and polarity, other factors seemed to play a role in the formation of the inkjet-printed micropatterns. If these factors can be identified and controlled, inkjet deposition of CNCs could become an attractive method for the fabrication of cellulose micropatterns.en
dc.description.degreePh. D.en
dc.identifier.otheretd-07192010-130550en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-07192010-130550/en
dc.identifier.urihttp://hdl.handle.net/10919/28337en
dc.publisherVirginia Techen
dc.relation.haspartNavarro_F_D_2010.pdfen
dc.relation.haspartNavarro_F_2010_Copyright.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectMicropatterningen
dc.subjectStreaming potentialen
dc.subjectXPSen
dc.subjectSize distributionen
dc.subjectAFMen
dc.subjectCellulose nanocrystalsen
dc.subjectInkjet printingen
dc.subjectParticle alignmenten
dc.titleCellulose Nanocrystals: Size Characterization and Controlled Deposition by Inkjet Printingen
dc.typeDissertationen
thesis.degree.disciplineMacromolecular Science and Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en
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