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Dissertation Information for Andrey V. Peresypkin

NAME:
- Andrey V. Peresypkin

DEGREE:
- Ph.D.

DISCIPLINE:
- Chemistry

SCHOOL:
- Emory University (USA) (2001)

ADVISORS:
- Fred M. Menger

COMMITTEE MEMBERS:
- Frank E. McDonald
- Lanny S. Liebeskind

MPACT Status: Fully Complete

Title: I. Combinatorial investigation of the self-assembly of zwitterionic gemini surfactants in aqueous and organic media. II. Multiarmed surfactants with dendritic and fenestrindan cores

Abstract: "In part I of chapter I, a large number of zwitterionic gemini surfactants were synthesized and their aggregation behavior in aqueous media was investigated as a function of chain length and asymmetry. It was found that the geminis self-assemble into micelles, coacervates, vesicles, and gels depending on the relative and overall lengths of the two hydrocarbon chains. A structural phase diagram was designed which plots the aggregation of the geminis as a function of the lengths of the two chains clearly demonstrating that coacervates are formed on the border between micelles and various bilayer structures. When the difference in length of the two chains becomes large, gels are formed. Various techniques were used for the characterization of the observed phases: dynamic light scattering, electron, light and polarized microscopy, differential scanning calorimetry, NMR (PGSE, liquid and solid-state), surface tensiometry, and rheology.

In part II of chapter I, a family of ""hybrid"" partially fluorinated zwitterionic gemini surfactants was synthesized and their self-assembly in organic and aqueous media was investigated. On the basis of phase-contrast, epi-fluorescense and electron microscopy, we found that these ""hybrids"" aggregate into ""reversed"" vesicles and tubules in non-polar organic media and into ""normal"" vesicles in aqueous media, being an example of ambidextrous amphiphiles.

In part I of chapter II, amphiphilic PAMAM dendrimers were synthesized having an average of 7 to 46 hydrophobic chains of varying lengths (C 10 -C 14 ) at the periphery. The behavior of the dendrimers in aqueous media was examined by pulse-gradient spin-echo NMR (FT-PGSE), dynamic light scattering, and surface tensiometry. It is concluded that dendrimers with 7-22 chains, each having 10-14 carbons, behave as unimolecular entities with chains coiled within the dendrimer interior. Only when the number of chains becomes large ( ca . ¡Ý 34) are chains forced externally promoting hydrophobically-induced self-assembly.

Part II of chapter II describes our preliminary results towards the synthesis of tetrasubstituted fenestrindan-based amphiphiles. Although some of the synthetic targets could be obtained, more work is required in order to improve the preparation of the various tetrasubstituted fenestrindan-based amphiphiles. Additionally, a synthetic strategy towards the synthesis of topologically nonplanar fenestrindan-based amphiphiles is proposed."

MPACT Scores for Andrey V. Peresypkin

A = 0
C = 0
A+C = 0
T = 0
G = 0
W = 0
TD = 0
TA = 0
calculated 2008-04-07 07:52:36

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