A Study of Langmuir Monolayers to Find a Template for Two-Dimensional Porphyrin Aggregation
Date
2003
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Producer
Director
Performer
Choreographer
Costume Designer
Music
Videographer
Lighting Designer
Set Designer
Crew Member
Funder
Rehearsal Director
Concert Coordinator
Advisor
Moderator
Panelist
Alternative Title
Department
Swarthmore College. Dept. of Physics & Astronomy
Type
Thesis (B.A.)
Original Format
Running Time
File Format
Place of Publication
Date Span
Copyright Date
Award
Language
en_US
Note
Table of Contents
Terms of Use
Full copyright to this work is retained by the student author. It may only be used for non-commercial, research, and educational purposes. All other uses are restricted.
Rights Holder
Access Restrictions
Terms of Use
Tripod URL
Identifier
Abstract
This study examined the phase behavior of four different Langmuir monolayers. The
four different monolayers were 1,2-Dipalimitoyl, sn-Glycero-3-Phophocholine (DPPC),
cetyltrimethylammonium bromide (CTAB), Isocarb-24 (1-24), and stearic acid (STA).
The monolayers were individually deposited on an aqueous surface and then subjected to
compression in a Langmuir trough. Surface pressure measurements were made
throughout the compressions using a Wilhelmy plate. Plots of surface pressure (SP) vs.
Mean molecular area (Mma), known as isotherms, were obtained for all of the
monolayers. The different regions of the isotherm curves were interpreted to signify
specific phases of the monolayers throughout the compression. The goal was to find a
monolayer that displayed a highly reproducible isotherm. This monolayer could then be
examined with a bound porphyrin in the subphase, as a possible template for future twodimensional
aggregation studies. Both DPPC and STA displayed highly reproducible
isotherms. The decision was made to use STA as the first subject with porphyrin in the
subphase. The porphyrin molecule that was added to the subphase was tetrakis (Nmethylpyridinium-
4-yl) porphine (abbreviated H2T4). This porphyrin was chosen
because it would ionically bind to the deprotonated carboxylic acid head group of the
stearic acid monolayer. A number of trials were run with various concentrations of H2T4
in the subphase. It was hypothesized that the binding of porphyrin to the monolayer
would occur in a manner leading to an "S" shaped binding curve. Unfortunately,
quantitative results did not verify the hypothesized shape of the binding curve.
Qualitatively, the study found evidence that the H2T4 molecules were binding to the
stearic acid molecules, but further studies must be done to establish the exact manner in
which the porphyrin binds to the Langmuir monolayer.