RSC Advances
Paper
signicant chemical interaction with the substrate interface,
9 J. Monahan and J. J. Wilker, Langmuir, 2004, 20, 3724–
and its crosslink density and modulus are being systematically
3729.
decreased with increasing monofunctional monomer concen- 10 P. A. Suci and G. G. Geesey, J. Colloid Interface Sci., 2000, 230,
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incorporation. The bulk material is becoming weaker, and with 11 C. Fant, K. Sott, H. Elwing and F. Hook, Biofouling, 2000, 16,
no increase in interfacial interaction like that observed for the 119–132.
Eug system, and more prominently, the EugOH system, the 12 L. A. Burzio and J. H. Waite, Biochemistry, 2000, 39, 11147–
MeEug thiol–ene adhesive fails at lower forces.
11153.
13 L. M. Hight and J. J. Wilker, J. Mater. Sci., 2007, 42, 8934–
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14 J. Heo, T. Kang, S. G. Jang, D. S. Hwang, J. M. Spruell,
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Conclusions
We have reported the synthesis of catechol-functionalized
thiol–ene polymer networks as photocurable adhesives, where
¨
the adhesive interactions are derived from 4-allylpyrocatechol – 15 R. Vendamme, N. Schuwer and W. Eevers, J. Appl. Polym. Sci.,
a monofunctional alkene readily obtained from natural prod- 2014, 131, DOI: 10.1002/app.40669.
ucts of Syzygium aromaticum ower buds (clove). The thiol–ene 16 M. Yu and T. J. Deming, Macromolecules, 1998, 31, 4739–
photopolymerization process enables rapid cure times, low 4745.
energy input, and solvent-free processing. Increasing the 17 H. Tatehata, A. Mochizuki, T. Kawashima, S. Yamashita and
concentration of EugOH in the thiol–ene networks resulted in H. Yamamoto, J. Appl. Polym. Sci., 2000, 76, 929–937.
improved adhesion on a variety of substrates, including glass, 18 M. Yu, J. Hwang and T. J. Deming, J. Am. Chem. Soc., 1999,
aluminium, steel, and marble. In addition, EugOH networks 121, 5825–5826.
were studied in comparison to networks containing eugenol 19 C. R. Matos-Perez, J. D. White and J. J. Wilker, J. Am. Chem.
and methyl eugenol. These comparative studies illuminate the Soc., 2012, 134, 9498–9505.
role catechol plays in dictating polymerization kinetics, 20 A. Stepuk, J. G. Halter, A. Schaetz, R. N. Grass and W. J. Stark,
mechanical, and thermomechanical properties, and adhesion Chem. Commun., 2012, 48, 6238–6240.
in these thiol–ene materials. While adhesive properties have 21 W. Ma, H. Xu and A. Takahara, Adv. Mater. Interfaces, 2014, 1,
been imparted to the model APE–PETMP thiol–ene resin by DOI: 10.1002/admi.201300092.
incorporating a natural product catechol containing monomer, 22 H. J. Meredith, C. L. Jenkins and J. J. Wilker, Adv. Funct.
this same synthetic technique could be applied to variety of Mater., 2014, 24, 3259–3267.
network materials leading to the generation of photocurable 23 E. M. White, J. E. Seppala, P. M. Rushworth, B. W. Ritchie,
´
sealants, hydrogels, and adhesives for dental, biomedical, and
advanced applications based on sustainable chemistries.
S. Sharma and J. Locklin, Macromolecules, 2013, 46, 8882–
8887.
24 H. Chung, P. Glass, J. M. Pothen, M. Sitti and
N. R. Washburn, Biomacromolecules, 2010, 12, 342–347.
25 J. Xue, T. Wang, J. Nie and D. Yang, J. Appl. Polym. Sci., 2013,
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Acknowledgements
The authors gratefully acknowledge nancial support from the
National Science Foundation (NSF DMR-1041853 and NSF 26 J. Xue, T. Wang, J. Nie and D. Yang, J. Photochem. Photobiol.,
CAREER DMR-1056817). BRD thanks the US Dept. of Education B, 2013, 119, 31–36.
GAANN Fellowship Program (Award # P200A120118) for nan- 27 R. Schwalm, UV Coatings: Basic, Recent Developments and New
cial support.
Applications, Elsevier, Amsterdam, London, 2007.
28 C. E. Hoyle and C. N. Bowman, Angew. Chem., Int. Ed., 2010,
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29 C. E. Hoyle, T. Y. Lee and T. J. Roper, J. Polym. Sci., Part A:
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Strength of Single-Lap-Joint Adhesively Bonded Metal
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