Influence of Chemical Composition on the Adhesion of Hydrogels inDry and Underwater Conditions
Megan Yankulov, Saranshu Singla, Amal Narayanan, Abraham Joy, Ali Dhinojwala
Department of Polymer Science, The University of Akron, Akron OH 44325
Email: [email protected]
In the production and use of biomedical devices,
wound dressings, and bone regeneration, underwater
adhesion is essential to its effectivity. However,
adhesion is limited in underwater environments
because water molecules will penetrate and create
gaps between surfaces and cause debonding at the
interface. Hydrogels have demonstrated superior
adhesion in underwater environments, despite their
chemical composition, which is surprising. 4,5 To
investigate this, polyethylene-glycol dimethacrylate
(PEGDMA) and 2-hydroxyethyl methacrylate (HEMA)
hydrogels were synthesized. Adhesion measurements
were done using JKR geometry to test the adhesion of
hydrogels in dry and wet conditions. Sum Frequency
Generation Spectroscopy (SFG) was used to examine
interaction strength and chemical composition at the
interface. Our results will provide insights into
designing hydrogels for wet adhesion applications.
1. Hydrogels demonstrated significantly lower
adhesion in underwater environments, regardless of
chemical composition.
2. HEMA-PEGDMA contained increased dry adhesion
through pull off force values when compared to
PEGDMA.
3. SFG analysis indicated presence of hydrocarbons as
well as hydroxyl signals at the interface.
4. Future work will be focused on conducting
additional SFG scans, as well as studying the
mechanical properties of the hydrogel utilizing
rheology measurements.
Motivation Experimental Design
1. Kaur, S.; Narayanan, A.; Dalvi, S.; Liu, Q.; Joy, A.; Dhinojwala, A. Direct Observation of the Interplay of Catechol Binding and Polymer Hydrophobicity in a Mussel-Inspired Elastomeric Adhesive. ACS Central Science 2018, 4, 1420-1429.2. Kurian, A.; Prasad, S.; Dhinojwala, A. Direct Measurement of Acid-Base Interaction Energy at Solid Interfaces. Langmuir 2010, 26, 17804-17807.3. Li, J.; Celiz, A. D.; Yang, J.; Yang, Q.; Wamala, I.; Whyte, W.; Seo, B. R.; Vasilyev, N. V.; Vlassak, J. J.; Suo, Z.; Mooney, D. J. Tough adhesives for diverse wet surfaces. Science 2017, 357, 378-381.4. Yang, J.; Bai, R.; Chen, B.; Suo, Z. Hydrogel Adhesion: A Supramolecular Synergy of Chemistry Topology and Mechanics. Adv. Funct. Mater. 2019, 1-27.5. Yi, H.; Lee, S.; Seong, M.; Kwak, M.; Jeong. Bioinspired reversible hydrogel adhesives for wet and underwater surfaces. Jour. Mat. Chem. 2018, 8064-8070.
Results and Discussion
Background
Conclusions and Future Work
References
Acknowledgements
Hydrogels are composed of over 80% water.4 This causes their superior underwater adhesion to be surprising, as water interferes with bonds between adhesive and substrate. However, numerous studies have indicated increased adhesion in underwater environments. 3,4
-4
-3
-2
-1
0
1
2
3
4
5
0 100 200 300 400 500 600 700 800 900
Forc
e (m
N)
Time (secs)
Force vs Time Dry PEGDMA slate
-2.5
-2
-1.5
-1
-0.5
0
0.5
0 100 200 300 400 500 600 700 800
Forc
e (m
N)
Time (seconds)
Force vs Time Underwater PEGDMA slate
Repeat 1 Repeat 2
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0 20 40 60 80 100 120 140
Pu
ll o
ff f
orc
e (m
N)
Time (minutes)
PEGDMA slate Pull Off Force vs Time
-1
-0.5
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Ave
rage
Pu
ll O
ff F
orc
e (m
N)
Average Pull Off Force of PEGDMA Lens in Dry and Wet Conditions
Lens 3 Dry Lens 3 Wet Lens 4 Dry
Lens 4 Wet Lens 5 Dry Lens 5 Wet
0
1
2
3
4
5
6
7
8
9
Pu
ll O
ff F
orc
e (m
N)
Average Pull Off Force of HEMA-PEGDMA in Dry and Wet Conditions
Dry Conditions 2mN preloadWet Conditions 2 mN preloadDry Conditions 4.0 mN preloadWet Conditions 4.0 mN preloadDry Conditions 6.0 mN preloadWet Conditions 6.0 mN preload
We would like to thank the National Science Foundation (DMR# 1659531) for the generous financial support. Many thanks to my laboratory instructors Saranshu Singla, Amal Narayanan, Dr. Ali Dhinojwala and all colleagues in Dr. Dhinojwala’s group for their helpful advice.
Hydrogels Show Promise in Tissue Repair and Wound Dressings3
Alginate-polyacrylamide hydrogels were synthesized with various bridging polymers and analyzed for their potential in tissue repair and wound dressings.
Results indicate hydrogels maintained high adhesion to various tissues in wet environments, were biocompatible, and diminished blood loss in wound dressing simulations.
Synthesis Adhesion
(PEGDMA)
(HEMA)Johnson Kendall Roberts Geometry (JKR)
Bulk water
Interface
-8.000
-6.000
-4.000
-2.000
0.000
2.000
4.000
6.000
8.000
0 200 400 600 800
Forc
e (m
N)
Time (seconds)
HEMA-PEGDMA Lens 2 Force vs Time in Dry Conditions
Preload force
Equilibration time
Pull off force
Detachment
Maximum pull off force was measured to indicate adhesive strength of the hydrogel in slate and lens form.
Hydrogel slates were difficult to cut and obtain a flat surface. Lens work better.
Hydrogels Demonstrate Significantly Decreased Underwater Adhesion
Spectroscopy
Air Scan
Dry Contact
Wet Contact
Air Scan
Dry Contact D2O Scan
PEGDMA Lens were analyzed in dry and wet contact. Further experiments were performed utilizing deuterium oxide to differentiate the water signals from sapphire surface OH groups.
The radius of each lens was measured to provide similar sized lens in each adhesion test performed.
Hydrogel
Photopolymerization by UV irradiation was utilized to create the following hydrogels:
Kaur, et al. ACS Central Science 2018,4,1420-1429
Kaur, et al. ACS Central Science 2018,4,1420-1429
https://orientalgrouplk.com/customer-erudition
https://www.dkfindout.com/us/human-body/skeleton-and-bones/living-bone/https://kikgel.com.pl/produkty/neoheal/
https://newatlas.com/temperature-controlled-hydrogel-movement/38865/
Spectroscopy
