March 2019 - Msepostdoc-list

Seminar Notice for Jerome Nash's Ph.D. Final Exam, Monday, March 18, at 2:30 p.m., in ARMS 1028. "Interfacial Rheology and the Controlled Fabrication/Disruption of Stabilized Emulsions"
by Son, Rosemary E 07 Mar '19

07 Mar '19

Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Interfacial Rheology and the Controlled Fabrication/Disruption of Stabilized Emulsions" By Jerome J. Nash Purdue MSE Ph.D. Final Exam Advisor: Professor Kendra A. Erk ABSTRACT Fluid interfaces containing surface-active species (e.g., surfactants, polymers, and particles) have rheological properties that are vital to the kinetic stability of emulsions. Many practical applications of emulsions necessitate superb stability during storage, such as in emulsion-based therapeutic delivery systems. While in other cases, stabilized systems are entirely unwanted (e.g., separating oil and aqueous phases in enhanced oil recovery and bilge water applications). Techniques for modulating emulsion stability are highly desired and are largely determined by the mechanics of the interfacially-trapped species. However, the utility of these techniques is often limited by difficulties in measuring and interpreting the rheological characteristics of complex fluid interfaces. Lack of control over interface formation during emulsification magnifies this problem, further obscuring relationships between interfacial rheology and bulk emulsion stability. Thus, the objectives of this research were to (1) elucidate these fundamental relationships through emulsion stability and interfacial rheological measurements, and (2) present innovative methodologies for modulating the kinetic stability of model oil-in-water emulsions using physical chemistry principles. Objective 1 was addressed by studying correlations between the dilatational rheology of single- and multi-component oil-water interfaces and the susceptibility to coalescence of the bulk systems they comprised. Oscillating pendant drop tensiometry was used to probe interfacial viscoelastic behavior, while dynamic light scattering and optical microscopy were used to characterize coalescence susceptibility in bulk oil-in-water emulsions. The magnitude of the low-frequency dilatational elastic modulus was shown to positively correlate with oil droplet coalescence resistance over time. Objective 2 was addressed by analyzing how physical chemistry principles can be applied to control various emulsion droplet destabilization phenomena and produce desirable bulk behavior. To this aim, two emulsion destabilization studies were performed; one related to the nanoparticle-induced flocculation of oil droplets in a dilute, electrostatically-stabilized emulsion and one related to the convective flows generated by the asymmetric dilatational rheology of coalescing droplets. The knowledge garnered from this body of work is highly relevant to academic and industrial emulsion formulators who seek inexpensive, yet robust methods for predicting, characterizing and tailoring the kinetic stability of oil-in-water emulsions. Date: Monday, March 18, 2019 Time: 2:30 P.M. Place: ARMS 1028

1 0

MSE 690 speaker Cabot Microelectronics Corporation, Friday, March 8, 2019 at 3:30pm/ARMS 1010
by Coar, Stacey L 07 Mar '19

07 Mar '19

[cid:image001.png@01D4D4C0.6FE73620] Stacey Stacey Coar Secretary/Development Assistant School of Materials Engineering Purdue University Neil Armstrong Hall of Engineering 701 West Stadium Ave. Room 2300 West Lafayette, IN 47907 765-494-4100 scoar(a)purdue.edu<mailto:scoar@purdue.edu>

1 0

MSE 690 guest speaker Dr. Jennifer Carter, Monday, March 4, 2019
by Coar, Stacey L 01 Mar '19

01 Mar '19

[cid:image001.jpg@01D4D04A.130EA070] Stacey Stacey Coar Secretary/Development Assistant School of Materials Engineering Purdue University Neil Armstrong Hall of Engineering 701 West Stadium Ave. Room 2300 West Lafayette, IN 47907 765-494-4100 scoar(a)purdue.edu<mailto:scoar@purdue.edu>

1 0

Seminar Notice for Aniruddha Jana Wednesday, March 6, at 9:00 a.m., in ARMS B071 "Modeling Degradation Mechanisms in Rechargeable Lithium-Ion Batteries"
by Son, Rosemary E 01 Mar '19

01 Mar '19

Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Modeling Degradation Mechanisms in Rechargeable Lithium-Ion Batteries" By Aniruddha Jana Purdue MSE Ph.D. Final Exam Advisor: Professor R. Edwin García ABSTRACT A physics-based, multiscale framework is presented to describe the degradation in rechargeable lithium-ion batteries. The framework goes beyond traditional (empirical) coulomb-counting approaches and enables the identification of different degradation regimes. Macroscopically, five degradation mechanisms: (i) solid electrolyte interphase (SEI) growth on the anode, (ii) electrolyte oxidation on the cathode, (iii) anode active material loss and (iv) cathode active material loss due to chemomechanical fracture, and (v) dendrite growth were identified and modeled. Great emphasis was placed on describing the physics of lithium dendrite growth in order to demonstrate five distinguishable regimes: thermodynamic suppression regime, incubation regime, tip-controlled growth regime, base-controlled growth regime, and mixed growth regime. Mesoscopically, three local dendrite growth mechanisms are identified: 1) electrochemical shielding, where there is practically no electrodeposition/electrodissolution, 2) stress-induced electrodissolution and electrodeposition on those interfaces directly facing each other, generating a self-sustained overpotential that pushes the dendrites towards the counter electrode, and 3) lateral plastic extrusion in those side branches experiencing non-hydrostatic stresses. Overall, the experimentally validated theoretical framework allows to fundamentally understand battery degradation and sets the stage to design high energy density and fast charging rechargeable batteries. Date: Wednesday, March 6, 2019 Time: 9:00 A.M. Place: ARMS B071

1 0