BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Events//NONSGML v1.0//EN
METHOD:PUBLISH
BEGIN:VEVENT
DTSTART;TZID="Pacific Time (US & Canada)":20220420T150000
DTEND;TZID="Pacific Time (US & Canada)":20220420T170000
SUMMARY:Chemistry PhD Final Defense — Kirill Gurdumov
LOCATION:Fulmer Hall
DESCRIPTION:Title: Self-Assembly Dynamics And Energetics At The Solution/Solid Interface: Concentration And Solvent Control\n\nAbstract: A comprehensive investigation on the formation dynamics and energetics of adlayer formation at the at the solution/solid interface has been performed using scanning tunneling microscopy (STM) with a custom solution flow cell design that offers new insight into the self-assembly process.  We herein investigate the growth, dynamics, and stability of a model non-covalent self-assembler -- Co(II) octaethylporphyrin at the solution/solution interface on the HOPG and Au(111) surfaces.  Real-time imaging of the nucleation and growth of the self-assembled layer was captured and studied by in-situ STM, and further explored using computational methods.  Flow studies at low concentration provide insight into early-stage kinetics and structural formation of a SAM.  It was found that the choice of organic solvent plays a dramatic role in the kinetics and structure of the SAM.    The role of the solvent was particularly strong in the case of 1,2,4-trichlorobenzene (TCB) on both HOPG and Au(111).  Under TCB, a very stable rectangular structure is formed and stabilized by solvent-incorporation.  A transition to a solvent free pseudo-hexagonal structure was only observed when extremely high concentrations of porphyrin were present in solution.  Similarly, in the case of CoOEP adsorbed on Au(111) under toluene, a solvent-incorporated rectangular structure was observed that also transitioned into a pseudo-hexagonal structure, but this transition occurred at much lower concentrations of porphyrin.  Toluene co-adsorption was not observed on HOPG.  When deposited from decane, a short-lived pseudo-rectangular structure was observed on Au(111) but not on HOPG.  Only the pseudo-hexagonal structure was observed in the porphyrin adlayer when 1-phenyloctane were used as a solvent.  These results provide insight into the balance of the intermolecular forces driving the self-assembly and the roles the choice of solvent and substate play in the formation process.
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:REMINDER
TRIGGER;RELATED=START:-PT00H15M00S
END:VALARM
END:VEVENT
END:VCALENDAR