Reversible Thermochromism in Polydiacetylenes
Garret GotthelfApril 11th, 2015Clemson UniversityReversible
Thermochromism in Polydiacetylenes
221
OutlinePDAsBio Sensors and The Discovery of
ReversibilityPCDA-CelluloseCondition changes: Wet N2, Dry N2,
Annealing, MercerizationPCDA SubstratesAlkali Metals and Alkaline
Earth MetalsDifferences in PCDA vs. PCDA-SaltsConclusions
Polydiacetylenes (PDAs)Alignment observed in organized states:
solid states, films, and liposomes. Can only occur with proper
geometry and spacing. Once polymerized, PDAs can be changed from a
planar to nonplanar state when certain stresses are placed on
it.
StressThe planar blue form has unbroken -electron overlap and a
full conjugation length. In the nonplanar red form -electron
overlap is reduced and conjugation length is decreased
Bio Sensors and The Discovery of Reversibility
PDA (4-butoxymethylcarbonyl urethane) as polymerized, left, and
heated to 60C, right.
60C
100C25CCotton Gauze coated with .1M NaOH and PCDA
PCDA-Cellulose and Different Conditions
10,12-Pentacosadiynoic acid (PCDA)Cotton GauzeFilter paper
Mercerization and Annealing
PCDA-Cellulose and Different Conditions cont.Acid Treatment,
Neutral Treatment, Base TreatmentWater TestNitrogen AtmosphereWet
and Dry
Mechanochromism vs. Thermochromism
PCDA SubstratesPCDA-MetalsAlkali MetalsAlkaline Earth Metals
RbCsPCDA-Amino Acids
PCDA-ArgininePCDA-NHS
Jiebin Pang,Lu Yang,Byron F. McCaughey,Huisheng Peng,Henry S.
Ashbaugh,C. Jeffrey Brinker,and, andYunfeng Lu*, The Journal of
Physical Chemistry B2006110(14), 7221-7225
7
Differences in PCDA-Salts
PCDA-Li: Blue Purple Red Back to PurplePCDA-K: Purple Red Orange
Back to Purple
PCDA-Cs: Dark Purple Orange Red Dark Red Orange and Purple
PCDA-Salts cont.
Note: Pure PCDA red and blue form shifted in triple bond
region
PCDAPCDA-KNote: PCDA has a distinct peaks while heat and cooling
where PCDA-K contains several significant peaks
Conclusion
PCDA interacts with alkali Metals to for a complex with the
alkali ions.Alkali ions change the flexibility of the structured
PCDA moleculesWhere do we go from here?
Acknowledgments
Dr. William T. Pennington
Sarah Hill
Dr. Paul Dawson, Dr. Han, Food Sci Dept
Dr. Timothy Hanks, Dr. Lon Knight, Furman Univ.
Clemson University
