+publisher:"Penn State University" +contributor:("Seong Han Kim, Committee Chair/Co-Chair")

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1. Luo, Jiawei. Understanding shear-induced hydrolysis reactions on soda lime silica glass surface.

Degree: 2018, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/15252jzl221

► Soda lime silica (SLS) glass is the most widely used glass materials in terms of mass in windows, glass bottles & containers, etc. One of… (more)

▼ Soda lime silica (SLS) glass is the most widely used glass materials in terms of mass in windows, glass bottles & containers, etc. One of the biggest challenge for SLS glass is its brittleness or prone to be damaged at ambient conditions. One important reason is that cracks propagation on SLS glass surface can be significantly accelerated by tensile stress induced corrosion reactions of amorphous silicate network, which breaks the Si-O-Si bonds to form two silanol groups, known as stress corrosion effect. It has also been found that stress corrosion reactions are faster with the increase of relative humidity (RH). The propagation of cracks will eventually lead to the failure of SLS glass. However, very little is known on the reactions between glass and water in the environment induced by interfacial shear, which results in the removal of SLS glass. Recently, it has been found that SLS glass shows unique response to interfacial shear in humid conditions through a ball-on-flat wear test. For most of the commercial flat glasses, including silica, borosilicate glasses, boroaluminosilicate glasses and aluminosilicate glasses, the amount of wear will increase as the humidity level increases. Only SLS glass shows wear resistance at high relative humidity. It is found that shear-induced hydrolysis reactions take place on SLS glass surface for medium and low RH conditions. Then this shear-induced hydrolysis reaction must be “suppressed” or have similar reaction rates of its reverse reactions (condensation of silanols) at high RH. One hypothesis is that Na+/H+ + H2O exchange could take place at high RH, which creates surface residual compressive stress at the meantime. Compressive stress which could lower the effective tensile stress on glass surface, is believed to stabilize or hinder the propagation of cracks. Then the amount of wear could also be lowered if the applied stress is not large enough to induce hydrolysis reactions. To test this hypothesis and explore the factors that govern the shear-induced reactions on SLS glass surface, effects of different structural units, surface mechanical properties and compressive stress, Na+/H+ + H2O exchange are investigated in this dissertation. It should be noted that these factors cannot be easily isolated. Therefore, multiple different treatments need to be performed to modify the surface chemical structures of SLS glass. These surface treatments include hydrothermal reactions, leaching in acid solution, thermal poling in controlled environment, ion-exchange with KNO3. The governing factors are determined through correlating the changes in surface chemical structure, mechanical properties with the wear behavior. It is found that surface mechanical properties, compressive stress and alteration layers created by Na+/H+ + H2O exchange are not responsible for SLS glass’s unique wear behavior at high RH. While no specific mechanism has been identified, mobile Na+ cations and silicate network structure are suggested to be the dominating factors. To better understand the amorphous… Advisors/Committee Members: Seong Han Kim, Dissertation Advisor/Co-Advisor, Chair%22%29&pagesize-30">Seong Han Kim, Committee Chair/Co-Chair, Kristen Ann Fichthorn, Committee Member, Manish Kumar, Committee Member, Carlo G. Pantano, Outside Member.

Subjects/Keywords: Soda lime silica glass; surface structure of glass; surface mechanical properties; shear-induced hydrolysis reactions; vibrational spectroscopy; wear behavior; surface chemistry

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APA (6^th Edition):

Luo, J. (2018). Understanding shear-induced hydrolysis reactions on soda lime silica glass surface. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/15252jzl221

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Luo, Jiawei. “Understanding shear-induced hydrolysis reactions on soda lime silica glass surface.” 2018. Thesis, Penn State University. Accessed January 18, 2021. https://submit-etda.libraries.psu.edu/catalog/15252jzl221.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Luo, Jiawei. “Understanding shear-induced hydrolysis reactions on soda lime silica glass surface.” 2018. Web. 18 Jan 2021.

Vancouver:

Luo J. Understanding shear-induced hydrolysis reactions on soda lime silica glass surface. [Internet] [Thesis]. Penn State University; 2018. [cited 2021 Jan 18]. Available from: https://submit-etda.libraries.psu.edu/catalog/15252jzl221.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Luo J. Understanding shear-induced hydrolysis reactions on soda lime silica glass surface. [Thesis]. Penn State University; 2018. Available from: https://submit-etda.libraries.psu.edu/catalog/15252jzl221

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

2. He, Xin. MECHANOCHEMISTRY OF ADSORBED MOLECULES AT TRIBOLOGICAL INTERFACES.

Degree: 2019, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/17191xuh118

► Mechanochemistry refers to reactions activated by mechanical force or stress. It is ubiquitous in engineering systems as well as daily life; but poorly understood because… (more)

▼ Mechanochemistry refers to reactions activated by mechanical force or stress. It is ubiquitous in engineering systems as well as daily life; but poorly understood because the reactions are taken place at solid tribological interfaces. The main challenges in mechanochemistry research are to identify the reactants and products at sliding interfaces, which can be overcome via vapor phase lubrication (VPL). The main questions in this work are the role of shear force or stress in mechanochemical reaction and how surface chemistry properties affect the reaction rate. This study investigated the molecular structure dependence of precursor molecules during mechanochemical reactions. Several monomers were studied to reveal the molecular structure dependence at tribological interfaces, including alpha-pinene (C10H16), pinane (C10H18) and n-decane (C10H18), which are all hydrocarbon precursors containing 10 carbon atoms. The friction coefficient of these molecules was around ~0.2 and they can be polymerized by mechanical shear. The molecules with ring structure (alpha-pinene and pinane) were found to produce more products compared with linear molecule n-decane. The modified Arrhenius-type equation is used to study the relationship between tribopolymerization yield and applied load; as well investigate how critical activation volume (ΔV*) is affected with the structure of monomers. The estimated ΔV* of alpha-pinene and pinane, which possess higher internal strain, showed the lowest activation volume, while the value is higher for n-decane (10%), which possesses low internal strain. The experimental results were then compared with molecular dynamic (MD) simulations with a ReaxFF reactive force field to reveal the physical meaning of activation volume. The tribo-polymerizable model reactants, allyl alcohol and alpha-pinene were studied. The results suggested that the precursor molecules first chemisorb on the surfaces through surface oxygen. During the sliding process, the precursors undergo partial distortion from its equilibrium conformation, corresponding to the critical activation volume for mechanochemical reactions. The activated intermediates polymerize through the formation of C-O-C ether bond, rather than direct C-C covalent bond. The effect of surface chemistry and the surrounding gas environment on mechanochemical polymerization reactions are also revealed. Mechanochemical reactions of alpha-pinene are studied on eight substrate materials – chemically reactive group (palladium, nickel, copper, stainless steel) and chemically inert group (gold, silicon oxide, aluminum oxide, DLC) The more reactive surfaces appear to be capable of chemisorbing alpha-pinene molecules even without the mechanical shear process. In the case of reactive surfaces, the critical activation volumes are relatively lower compared to that only capable of physisorption. Such chemisorption process can be significantly enhanced through the oxidative gas environment, in turn increasing tribochemical reactivity. When the water is introduced to the… Advisors/Committee Members: Seong Han Kim, Dissertation Advisor/Co-Advisor, Chair%22%29&pagesize-30">Seong Han Kim, Committee Chair/Co-Chair, Xueyi Zhang, Committee Member, Themis Matsoukas, Committee Member, Adrianus C Van Duin, Outside Member, Seong Han Kim, Program Head/Chair.

Subjects/Keywords: tribology; lubrication; mechanochemistry; surface science

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

He, X. (2019). MECHANOCHEMISTRY OF ADSORBED MOLECULES AT TRIBOLOGICAL INTERFACES. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/17191xuh118

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

He, Xin. “MECHANOCHEMISTRY OF ADSORBED MOLECULES AT TRIBOLOGICAL INTERFACES.” 2019. Thesis, Penn State University. Accessed January 18, 2021. https://submit-etda.libraries.psu.edu/catalog/17191xuh118.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

He, Xin. “MECHANOCHEMISTRY OF ADSORBED MOLECULES AT TRIBOLOGICAL INTERFACES.” 2019. Web. 18 Jan 2021.

Vancouver:

He X. MECHANOCHEMISTRY OF ADSORBED MOLECULES AT TRIBOLOGICAL INTERFACES. [Internet] [Thesis]. Penn State University; 2019. [cited 2021 Jan 18]. Available from: https://submit-etda.libraries.psu.edu/catalog/17191xuh118.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

He X. MECHANOCHEMISTRY OF ADSORBED MOLECULES AT TRIBOLOGICAL INTERFACES. [Thesis]. Penn State University; 2019. Available from: https://submit-etda.libraries.psu.edu/catalog/17191xuh118

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

3. Hsiao Liao, Erik. CATIONIC POLYMER LUBRICANT (CPL): A NEW BOUND AND MOBILE BOUNDARY LUBRICANT WITH SELF-HEALING CAPABILITIES .

Degree: 2011, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/12061

► The boundary film formation and lubrication effects of low-molecular-weight silicone molecules with cationic side groups were studied. Poly-(N,N,N-trimethylamine-3-propylmethylsiloxane-co-dimethylsiloxane) iodide was synthesized and deposited on silicon… (more)

▼ The boundary film formation and lubrication effects of low-molecular-weight silicone molecules with cationic side groups were studied. Poly-(N,N,N-trimethylamine-3-propylmethylsiloxane-co-dimethylsiloxane) iodide was synthesized and deposited on silicon oxide surfaces to form a bound-and-mobile lubricant film. The effects of the ionically bound layer and mobile multilayers were investigated. Both nano- and macro-scale tribological tests revealed superior lubrication performance of the silicon molecule with cationic side chains over the neutral silicon molecule (which was modeled with polydimethylsiloxane with the same molecule weight). The multilayer films exhibited characteristic topographic features due to ionic interactions within the polymeric film. In the macro-scale, the effects of ionic content, environmental condition, and advantage of the bound layer on self-healing will be discussed to demonstrate the wear resistance and self-healing capability. The multilayer spreading rates were estimated to be ~10^-11 m2/s. In the nano-scale, the results of disjoining pressure and viscosity measurements help understand the lateral spreading of the mobile layer and identify the mobile species. The mobile species are the reduced tertiary amine form of CPL. The hydrophobic but hygroscopic properties of CPL are also investigated with SFG and ATR-IR. The CPL-coated surfaces are hydrophobic which prevents the detrimental effects of humidity on wear of silicon. In addition, the hygroscopic nature of CPL allows humidity to be absorbed into the film, which enhances the self-healing capabilities. Finally, by texturing the silicon surface with nanowells, self-healing is enhanced when the nanowells are filled with CPL. The nanowells serve as CPL reservoirs that are readily available for self-healing within the wear track for faster cycle intervals. However, the nanowells deteriorate the self-healing from surrounding the contact region due to the refilling of the empty nanowells. Advisors/Committee Members: Seong Han Kim, Dissertation Advisor/Co-Advisor, Chair%22%29&pagesize-30">Seong Han Kim, Committee Chair/Co-Chair, Themis Matsoukas, Committee Member, Joseph Manuel Perez Sr., Committee Member, Evangelos Manias, Committee Member.

Subjects/Keywords: Self-healing; Lubricant; Polymer; Tribology; AFM

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Hsiao Liao, E. (2011). CATIONIC POLYMER LUBRICANT (CPL): A NEW BOUND AND MOBILE BOUNDARY LUBRICANT WITH SELF-HEALING CAPABILITIES . (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/12061

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Hsiao Liao, Erik. “CATIONIC POLYMER LUBRICANT (CPL): A NEW BOUND AND MOBILE BOUNDARY LUBRICANT WITH SELF-HEALING CAPABILITIES .” 2011. Thesis, Penn State University. Accessed January 18, 2021. https://submit-etda.libraries.psu.edu/catalog/12061.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Hsiao Liao, Erik. “CATIONIC POLYMER LUBRICANT (CPL): A NEW BOUND AND MOBILE BOUNDARY LUBRICANT WITH SELF-HEALING CAPABILITIES .” 2011. Web. 18 Jan 2021.

Vancouver:

Hsiao Liao E. CATIONIC POLYMER LUBRICANT (CPL): A NEW BOUND AND MOBILE BOUNDARY LUBRICANT WITH SELF-HEALING CAPABILITIES . [Internet] [Thesis]. Penn State University; 2011. [cited 2021 Jan 18]. Available from: https://submit-etda.libraries.psu.edu/catalog/12061.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Hsiao Liao E. CATIONIC POLYMER LUBRICANT (CPL): A NEW BOUND AND MOBILE BOUNDARY LUBRICANT WITH SELF-HEALING CAPABILITIES . [Thesis]. Penn State University; 2011. Available from: https://submit-etda.libraries.psu.edu/catalog/12061

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

4. Nair, Sujith. Synthesis and application of functional polymeric nanofibers .

Degree: 2008, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/7666

► The central objectives of this thesis are to develop engineering based approaches for the synthesis of functional (conducting) nanofibers and biocatalytic nanofibers; and to exploit… (more)

▼ The central objectives of this thesis are to develop engineering based approaches for the synthesis of functional (conducting) nanofibers and biocatalytic nanofibers; and to exploit the use of biocatalytic nanofibers for enzyme based applications. Despite several advances in template synthesis, the release and re-capture of nanomaterials produced within the template still remains a critical issue. This difficulty may be avoided if one can produce and transfer nanomaterials directly to the target substrate while they are produced from an ordered array of nano-scale reactors without disintegrating the reactor array. The first part of this thesis aims at developing a nano-manufacturing technique for the continuous synthesis and extrusion of ordered arrays of polymeric nanofibers from nanoporous templates. As a poof of concept the synthesis and extrusion of polyethylene nanofibers by heterogeneous Ziegler-Natta polymerization within nanochannels of robust anodized aluminum oxide membranes is described. The second part of this thesis aims at the development of nano-manufacturing techniques for the synthesis of conducting polymer composite nanofibers. Conducting polymers such as polypyrrole and poly (3, 4-ethylenedioxythiophene) have a great potential in the field of flexible electronics, nano-electronics and bio-sensing. However, despite its superior thermal and environmental stability it suffers from being intractable. Conducting polymers such as polypyrrole is insoluble and infusible in almost all solvents - a limitation that prevents it from being processed into useful devices, especially at the nanoscale. Due to the same reason, nanofibers of these polymers cannot be directly fabricated by convenient methods such as electrospinning. To address this issue, electrically conducting composite nanofibers are produced by a two step process. First, electrospinning is used to synthesize template fibers loaded with suitable oxidants. Second, the template fibers are exposed to the monomer vapors which diffuse into the templates and are oxidized to form the conducting polymer. Electrically conducting polypyrrole-polyethylene-oxide (PPy-PEO) nanofibers, polypyrrole shell-polystyrene core (PPy-PS) nanofibers and poly (3, 4-ethylenedioxythiophene) shell –polystyrene core (PEDOT-PS) nanofibers were synthesized in this way. The effect of two different oxidants – ferric chloride and ferric toluenesulfonate, on the polymerization process was also investigated. The nonwoven mat of nanofibers was also exploited for gas sensing applications. The third part of this thesis focuses on the fabrication of nanofibers for enzyme based biocatalytic applications. Fabrication of highly stable enzyme coatings on the nanofibers is described. To improve the enzyme loading onto electrospun nanofibers an alcohol dispersion technique has been formulated. The dispersed nanofibers containing covalently attached enzymes or crosslinked enzyme coatings have been exploited as continuous flow reactors. Stability of the enzyme coatings in highly reactive… Advisors/Committee Members: Chair%22%29&pagesize-30">Seong Han Kim, Committee Chair/Co-Chair, Michael V Pishko, Committee Member, Darrell Velegol, Committee Member, Qing Wang, Committee Member.

Subjects/Keywords: electrospinning; polyethylene; polypyrrole

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Nair, S. (2008). Synthesis and application of functional polymeric nanofibers . (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/7666

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Nair, Sujith. “Synthesis and application of functional polymeric nanofibers .” 2008. Thesis, Penn State University. Accessed January 18, 2021. https://submit-etda.libraries.psu.edu/catalog/7666.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Nair, Sujith. “Synthesis and application of functional polymeric nanofibers .” 2008. Web. 18 Jan 2021.

Vancouver:

Nair S. Synthesis and application of functional polymeric nanofibers . [Internet] [Thesis]. Penn State University; 2008. [cited 2021 Jan 18]. Available from: https://submit-etda.libraries.psu.edu/catalog/7666.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Nair S. Synthesis and application of functional polymeric nanofibers . [Thesis]. Penn State University; 2008. Available from: https://submit-etda.libraries.psu.edu/catalog/7666

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

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