Adsorption of Amphoteric and Nonionic Polymers on Model Thin Films

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dc.contributor.advisor Kirill Efimenko, Committee Member en_US
dc.contributor.advisor Dimitris S. Argyropoulos, Committee Member en_US
dc.contributor.advisor Martin A. Hubbe, Committee Member en_US
dc.contributor.advisor Orlando J. Rojas, Committee Chair en_US Song, Junlong en_US 2010-04-02T18:50:11Z 2010-04-02T18:50:11Z 2008-08-19 en_US
dc.identifier.other etd-07252008-112350 en_US
dc.description.abstract Understanding the adsorption behaviors of polymers from solution is critical in applications such as fiber processing, specifically in the development of fiber bonding and lubrication. Therefore, in situ and real time Quartz Crystal Microbalance and Surface Plasmon Resonance were employed to monitor the adsorption of hydrosoluble polymers (including amphoteric and nonionic macromolecules) on ultrathin films of cellulose, polypropylene, polyethylene, nylon and polyethylene terephthalate (typical paper and textile materials). The extent of adsorption of amphoteric polymers on cellulose (and also on silica) depended on the charge density of the substrate and pH of the medium. More importantly, the adsorbed amount exceeded that found in the case of simple polyelectrolytes. We hypothesized that this extensive adsorption is the result of a polarization effect produced by the charged substrate, which also determined the characteristics (thickness and viscoelastivcity) of the adsorbed layers as well as bonding abilities. Surface active polymers including diblock polyalkylene glycols and triblock polymers (based on ethylene- and propylene- oxide) as well as silicone surfactants were used to study the formation of boundary layers that are relevant in fiber lubrication. Adsorption isotherms for the nonionic polymers followed a Langmuirian behavior in which the hydrophobic effect was a major driving mechanism. The molecular mass of the polymer influenced markedly adsorption and, compared to typical hydrocarbon surfactants, silicone-based surfactants showed a higher surface activity and affinity with the tested hydrophobic surfaces. Lateral force microscopy and molecular dynamics simulation were used to illustrate boundary lubrication. It was concluded that surface-active molecules form robust self assembled (lubricant) layers that withstand high shear forces and are able to control friction and abrasion due to the unique molecular structures they form at the interface. Overall, it is anticipated that this thesis will contribute to the elucidation of the relationship between the structure and chemical nature of the adsorbing polymers and their respective interfacial behaviors. en_US
dc.rights I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dis sertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to NC State University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. en_US
dc.subject Nonionic polymers en_US
dc.subject Polyampholytes en_US
dc.subject Boundary lubrication en_US
dc.subject Silicone surfactants en_US
dc.subject Adsorption en_US
dc.title Adsorption of Amphoteric and Nonionic Polymers on Model Thin Films en_US PhD en_US dissertation en_US Wood and Paper Science en_US

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