1.  Literature Value (cm-1) (chemical shift ppm, splitting, int.)
Sticky Like a Mussel: Synthesis of a Biomimetic Adhesive Polymer – Progress So Far!
Presented by: Bryce Birchfield and Justin Dingman
Sponsored by: Dr. Ronda Bard
University of Portland
April 12, 2016
ABSTRACT:
Mussels secrete a polypeptide used to adhere to various objects in aquatic environments. Although previous groups have developed methods for mimicking this compound, we set out to develop a safer and more practical scheme, which can be practiced by undergraduate organic chemistry laboratory students. Since the adhesive properties of the 3,4-dihydroxy polymer have been previously studied, we focused on generating a 3,5-dihydroxy polymer. This process involves a five-phase reaction of which the first reaction has been successfully completed and analyzed.
INTRODUCTION:
Biological substances, such as mussel adhesives have played a significant role towards the inspiration of developing synthetic adhesive polymers. Adhesives are an important part of daily life as they carry a wide array of applications, such as construction, automobile manufacturing and orthopedics. Due to such a high demand for adhesives in the marketplace, laboratories are beginning to generate mussel mimetic polymers from polypeptides, polystyrenes and polyurethanes. This study has set out to accomplish the synthesis of poly[(3,5-dihydroxystyrene)-co-styrene], a mussel mimicking polymer which has never before been investigated for its adhesive properties. We are also interested in creating poly[(3,4-dihydroxystyrene)-co-styrene] using the shortened methods for synthesis of our 3,5-dihydroxy polymer.
PROJECT OBJECTIVES:
Develop a scheme for creation of the mimetic polymer which can be replicated by organic chemistry students.
Complete first phase of five-step reaction: Synthesis of methyl 3,5-Bis(benzyloxy)benzoate from methyl 3,5-dihydroxybenzoate by addition of benzyl bromide.
Before end of semester, complete the second phase: Reduction of 3,5-bis(benzyloxy)benzoate to 3,5-bis(benzyloxy)benzaldehyde using DIBAL.
Next semester: Complete synthesis of polymer. Analyze adhesive properties through shear testing performed at Shiley School of Engineering.
ANALYSIS OF FIRST STEP
Melting point (C): (lit: 68-69)1
Percent Yield: 57% IR
1H NMR
ERRORS & FUTURE WORK
Slight depression of the melting point may point to contamination of the product. The compound has not been recrystallized to remove impurities. In addition, a peak at ppm in the HNMR spectrum also indicates a small amount of contamination. Upon completion of the five-step reaction adhesion studies will then be performed. Furthermore, because adhesives serve several uses we would like to develop a polymer that can be safely handled by humans. A possible solution would be to create the same polymer with a silicon backbone.
CONCLUSION
Adhesives secreted by mussels are mainly comprised of DOPA-containing proteins. These proteins can be mimicked via synthetic polymers where catechol groups are attached to the polymer chain. In this study we mimic the adhesive with poly[(3,5-dihydroxystyrene)-co-styrene], where the protein backbone is represented by polystyrene and the catechol groups replicate DOPA. Although DOPA has hydroxyl groups attached to the 3 and 4 positions on its benzene ring, we set out to further explore the adhesive properties of the polymer if the hydroxyl groups were placed in different positions around the ring. To create the mimicking polymer, we have developed a five-step reaction, which can be replicated in undergraduate laboratories. Currently, we have completed the first phase of the five-step reaction.
SYNTHESIS
RESULTS
Functional Group
 Literature Value (cm-1)
Aromatic C  H
Aliphatic C  H
Ester carbonyl C=O
1715
Aromatic C=C
1600
1596
Hydrogen Environment
 Literature Values
(chemical shift ppm, splitting, int.)
 Experimental Values
OCH3
3.90, (s), 3H
3.89 (s), 3H
OCH2Ph
5.06, (s), 4H
Aromatic H (4 position)
6.80, (t), 1H
Aromatic H
, (m), 12H
, (m), 12H
AIBN
REFERENCES AND ACKNOWLEDGEMENTS
1. Li, W.; Li, H.; Li, Y.; Hou, Z. Total Synthesis of (+) quadrangularin A. Angewanndte Chemie, I nternational Edition (45),
2. Matos- Pérez, C.R.; White, J.D.; Wiler, J.J. Journal of the American Chemical Society. 2012, 134 (22),
3. van Nunen, J.; Folmer, B.; Nolte, R. Induction of Liquid Crystallinity by Host-Guest Interactions. Journal of American Chemical Society
Special Thanks to Prof. Laura Schacherer, Prof. Rachel Hutchinson and student, Kevin Jones.