Photo-Induced Assembly of Spiropyran Polymers with Different Metal Ions by Hillary straub
1. Photo-Induced Assembly of
Spiropyran Polymers with Different
Metal Ions
Hillary Straub1,2, Larisa Florea1, Dermot Diamond1
1 Insight Centre for Data Analytics, National Centre for Sensor
Research, School of Chemical Sciences, Dublin City University,
Dublin 9, Ireland
2Department of Chemistry, University of Kansas, Lawrence, USA
3. Background and Applications
2
Thermoresponsive polymers
incorporating spiropyran have
been used in light-induced
aggregation.
Photo-induced conformational
changes have been observed with
spiropyrans functionalized on
polypeptides.
DOI: 10.1039/c3cs60181a
8. Photo-Induced Me2+ Aggregation
Explore photo-induced aggregation by
varying the given parameters:
solvent environment
Me2+ Identity
The ratio of Me2+ compared to the number of
MC units in the Polymer chain
The length of the polymer chain
7
9. 75 Length Polymer
Cu2+:MC
Units
Ratio of DMF (1mg/mL) to water
1:1 1:2.3 1:4 1:9
1:2 Prior UV UV
1:4 Prior UV
1:8 UV UV
1:16 UV
1:32
Results: Cu2+ Induced Aggregation
300 Length Polymer
Cu2+:MC
Units
Ratio of DMF (1mg/mL) to water
1:1 1:2.3 1:4 1:9
1:2 Prior UV UV UV
1:4 Prior UV UV
1:8 Prior UV
1:16 UV
1:32 UV
1:64 UV
The longer chain polymer
shows a larger range of results.
Both polymer chain lengths
demonstrate that as the
concentration of polymer
decreases and the amount of
water in the sample increases,
the aggregation is limited or
unseen.
8
10. The Affect of Water in the Sample Vs.
the Affect of the Polymer Concentration
300 Length Polymer
Cu2+:MC
Units
Ratio of DMF to water
(amount of Polymer in 1 mL Sample)
1:1 (.5mg) 1:9 (.5mg) 1:9 (.1mg)
1:2 Prior Prior UV
1:4 Prior Prior
1:8 Prior Prior
1:16 UV UV
1:32 UV UV
1:64 UV
Although water has a
slight affect on the
aggregation of the
samples, the
concentration of the
polymer in the sample
is shown to be a more
important factor in the
aggregation of samples
in ratios of DMF and
water.
9
12. Results: Testing Different Metal Ions
75 Length Polymer
1:1 DMF:water
(.5mg PMR in
1mL Sample)
Me2+:MC
units
Cu2+
Co2+
Ni2+
Zn2+
Ca2+
1:2 Prior UV UV UV
1:4 Prior UV
1:8 UV UV
1:16 UV
1:32
300 Length Polymer
1:1 DMF:water
(.5mg PMR in
1mL Sample)
Me2+ : MC
units
Cu2+
Co2+
Ni2+
Zn2+
Ca2+
1:2 Prior UV UV UV Prior
1:4 Prior UV UV
1:8 Prior UV UV
1:16 UV
1:32 UV
1:64 UV
**Copper was the only
metal ion to cause photo-
induced aggregation in
samples with an
increasing amount of
water and decreasing
concentration of polymer.
**Nickel and Zinc
samples also showed
aggregation in the
ratio 1:2.3 of DMF :
water, but not in
samples with lower
concentration of
polymer. Red
indicates ratios that
have yet to be tested.
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13. De-aggregation
Me2+
Me2+, UV
- Me2+, White light
• De-aggregation could not be achieved by photo-irradiation
• Irradiation with white light caused the aggregates to turn from
purple to white
• Similar results were obtained with all of the metal ions studied
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14. SEM Images
Left: 1:1 DMF: Water with 1:4 Cu2+:MC units; Top Right: 1:1 DMF: Water with 1:2 Zn2+:MC units;
Bottom Right: 1:1 DMF: Water with 1:2 Ni2+:MC units.
SEM images of aggregates acquired 30 July 2014
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15. Conclusions
The length of the polymer chain facilitates in the
aggregation of the samples
A higher ratio of organic solvent compared with water
showed a larger range of results, caused by the higher
amounts of polymer in the samples.
Lower ratios of metal ion: MC units cause aggregation;
The samples with higher amounts of polymer in the
samples and the samples with the metal ions with higher
binding affinities showed successful aggregation with
lower ratios of metal ions: MC units
Successful aggregation was seen in the metal ions with
less binding affinity
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