In conclusion, we proposed the bioinspired antifouling strategy that can fundamentally prevent surface fouling based on deliberate induction of strong vortices and high shear flows using undulatory topographical waves of the magnetic field-responsive dynamic composite. To achieve the research purpose and goal, detailed objectives were carried out in each chapter.
The first research objective was to analyze the batoid’s pectoral fin structure, undulatory gait, and ambient flow characteristics. In Chapter II, a cross-sectional histochemical structure analysis of batoid fish’s pectoral fin was conducted. Undulatory pectoral fin gait with ambient vortices generation was also analyzed subsequently.
The second research objective was to design and fabricate artificial structure with the optimized material composition. In Chapter II, based on the preliminary studies about the batoid fish, the magneto-responsive multilayered structure was designed and manufactured with four different materials. After that, the surface undulation, which was mimicked by batoid’s fin gait, was observed using monochrome and fluorescence imaging. Numerical analysis of magnetic field-induced deformation was conducted based on the theoretical equations. Then the geometric parameters including deformation depth and diameter were modulated by controlling the thickness of the resilient damping layer. With these procedures, the bioinspired multilayered composite was developed and the dynamic undulatory surface motion was realized.
The third research objective was to conduct the fluid-structure interaction analysis of the developed system. In Chapter III, particle image velocimetry was used to observe the generation of strong fluidic velocity change and ambient vortices by dynamic undulation. Finite element analyses were also conducted to study velocity field change, particle velocity and trajectories theoretically. The numerical prediction was in high accordance with the experimental observation. The rotational particle trajectories above the dynamic undulatory composite indirectly proved that the vortex generation could act as a barrier to foulants. Furthermore, the magnitudes of vorticity and wall shear stress were modulated and maximized for the increased antifouling property, by controlling the actuation period and deformation depth.
The fourth research objective was to analyze bacterial behavior inside the characterized flow and quantify antifouling properties. The real-time tracking of bacterial cells under static and dynamic state showed that the undulatory surface waves induce local and global vortices over the dynamic composite, fundamentally inhibiting the attachment of foulants to the surface. Moment scaling spectrum analyses also back up the results. Accordingly, the dynamic composite exhibits outstanding antifouling performance against E. coli with a simple topographical motion without surface
54
modification using chemicals or nanostructures. Quantification of the antifouling performance against E. coli was conducted using % areal coverage and CFU.
The last research objective was to enhance the antifouling performance and to propose a field of application. It was proven that the antifouling performance could be increased with proper modulation of actuation frequency and deformation depth. Nanoneedle array and MPC were added to the skin layer of dynamic undulatory composite for further enhanced antifouling performance. As the application of this research, the artificial medical tube with antifouling inner wall surface was demonstrated.
Figure 46. Conclusion and perspectives
Although we utilized a magnetic field-based actuation in this study to drive the surface undulations, electromagnetic field system with controlled electric current frequency can be adopted to manipulate surface undulation in a fixed set-up without moving the permanent magnet. Other physical stimuli such as light, heat or electric field could also be harnessed to realize the topographical change.
Furthermore, as the active type of antifouling approach requires energy consumption, passive and dynamic mechanisms that can generate undulatory surface waves in a more energy-efficient way by
55
external flow or other environmental forces can be employed to devise dynamic antifouling surfaces with broader applicability. With the highly fluctuating flow-based outstanding antifouling property, the dynamic composite with coordinated undulatory topographical waves could contribute to the development of new-concept bioinspired dynamic and sustainable antifouling strategies.
56
References
[1] K. Baek, J. Liang, W. T. Lim, H. Zhao, D. H. Kim, and H. Kong, "In situ assembly of antifouling/bacterial silver nanoparticle-hydrogel composites with controlled particle release and matrix softening," ACS Appl. Mater. Interfaces, vol. 7, no. 28, pp. 15359-15367, 2015.
[2] D. O. Schairer, J. S. Chouake, J. D. Nosanchuk, and A. J. Friedman, "The potential of nitric oxide releasing therapies as antimicrobial agents," Virulence, vol. 3, no. 3, pp. 271-279, 2012.
[3] C. M. Magin, S. P. Cooper, and A. B. Brennan, "Non-toxic antifouling strategies," Mater.
Today, vol. 13, no. 4, pp. 36-44, 2010.
[4] K. Ishihara, T. Ueda, and N. Nakabayashi, "Preparation of phospholipid polylners and their properties as polymer hydrogel membranes," Polym. J., vol. 22, no. 5, p. 355, 1990.
[5] L. Jiang, Y. Zhao, and J. Zhai, "A lotus‐leaf‐like superhydrophobic surface: a porous microsphere/nanofiber composite film prepared by electrohydrodynamics," Angew. Chem. Int.
Ed., vol. 43, no. 33, pp. 4338-4341, 2004.
[6] C. M. Bhadra et al., "Antibacterial titanium nano-patterned arrays inspired by dragonfly wings," Sci. Rep., vol. 5, p. 16817, 2015.
[7] A. K. Epstein, T.-S. Wong, R. A. Belisle, E. M. Boggs, and J. Aizenberg, "Liquid-infused structured surfaces with exceptional anti-biofouling performance," Proc. Natl. Acad. Sci., vol.
109, no. 33, pp. 13182-13187, 2012.
[8] J. F. Schumacher, C. J. Long, M. E. Callow, J. A. Finlay, J. A. Callow, and A. B. Brennan,
"Engineered nanoforce gradients for inhibition of settlement (attachment) of swimming algal spores," Langmuir, vol. 24, no. 9, pp. 4931-4937, 2008.
[9] K.-C. Park, H. J. Choi, C.-H. Chang, R. E. Cohen, G. H. McKinley, and G. Barbastathis,
"Nanotextured silica surfaces with robust superhydrophobicity and omnidirectional broadband supertransmissivity," ACS Nano, vol. 6, no. 5, pp. 3789-3799, 2012.
[10] Y. Rahmawan, L. Xu, and S. Yang, "Self-assembly of nanostructures towards transparent, superhydrophobic surfaces," J. Mater. Chem. A, vol. 1, no. 9, pp. 2955-2969, 2013.
[11] C. Hao et al., "Superhydrophobic-like tunable droplet bouncing on slippery liquid interfaces,"
Nat. Comm., vol. 6, p. 7986, 2015.
[12] J. H. Kim et al., "Remote manipulation of droplets on a flexible magnetically responsive film," Sci. Rep., vol. 5, p. 17843, 2015.
[13] S.-H. Lee et al., "Tunable multimodal drop bouncing dynamics and anti-icing performance of a magnetically responsive hair array," ACS Nano, vol. 12, no. 11, pp. 10693-10702, 2018.
[14] G. D. Bixler, A. Theiss, B. Bhushan, and S. C. Lee, "Anti-fouling properties of microstructured surfaces bio-inspired by rice leaves and butterfly wings," J. Colloid Interface Sci., vol. 419, pp. 114-133, 2014.
57
[15] H. J. Ensikat, P. Ditsche-Kuru, C. Neinhuis, and W. Barthlott, "Superhydrophobicity in perfection: the outstanding properties of the lotus leaf," (in English), Beilstein J Nanotech, vol.
2, pp. 152-161, Mar 10 2011. [Online]. Available: <Go to ISI>://WOS:000300014000004.
[16] S. Rigo et al., "Nanoscience-Based Strategies to Engineer Antimicrobial Surfaces," Adv. Sci., vol. 5, no. 5, p. 1700892, May 2018, doi: 10.1002/advs.201700892.
[17] P. Zhang, L. Lin, D. Zang, X. Guo, and M. Liu, "Designing Bioinspired Anti-Biofouling Surfaces based on a Superwettability Strategy," Small, vol. 13, no. 4, Jan 2017, doi:
10.1002/smll.201503334.
[18] C. M. Magin, C. J. Long, S. P. Cooper, L. K. Ista, G. P. Lopez, and A. B. Brennan,
"Engineered antifouling microtopographies: the role of Reynolds number in a model that predicts attachment of zoospores of Ulva and cells of Cobetia marina," (in English), Biofouling, vol. 26, no. 6, pp. 719-727, 2010. [Online]. Available: <Go to ISI>://WOS:000281887000010.
[19] I. Zada, W. Zhang, P. Sun, M. Imtiaz, W. Abbas, and D. Zhang, "Multifunctional, angle dependent antireflection, and hydrophilic properties of SiO2 inspired by nano-scale structures of cicada wings," (in English), Appl. Phys. Lett., vol. 111, no. 15, Oct 9 2017. [Online].
Available: <Go to ISI>://WOS:000413196100044.
[20] G. D. Bixler and B. Bhushan, "Biofouling: lessons from nature," Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, vol. 370, no. 1967, pp. 2381-2417, 2012.
[21] M. Al-Fori, S. Dobretsov, M. T. Z. Myint, and J. Dutta, "Antifouling properties of zinc oxide nanorod coatings," (in English), Biofouling, vol. 30, no. 7, pp. 871-882, 2014. [Online].
Available: <Go to ISI>://WOS:000340138100010.
[22] V. B. Damodaran and N. S. Murthy, "Bio-inspired strategies for designing antifouling biomaterials," Biomaterials research, vol. 20, no. 1, p. 18, 2016.
[23] C.-H. Xue, X.-J. Guo, J.-Z. Ma, and S.-T. Jia, "Fabrication of robust and antifouling superhydrophobic surfaces via surface-initiated atom transfer radical polymerization," ACS Appl. Mater. Interfaces, vol. 7, no. 15, pp. 8251-8259, 2015.
[24] L. Zheng, H. S. Sundaram, Z. Wei, C. Li, and Z. Yuan, "Applications of zwitterionic polymers," React. Funct. Polym., vol. 118, pp. 51-61, 2017.
[25] J. C. Tiller, C.-J. Liao, K. Lewis, and A. M. Klibanov, "Designing surfaces that kill bacteria on contact," Proc. Natl. Acad. Sci., vol. 98, no. 11, pp. 5981-5985, 2001.
[26] N. Liu et al., "Nitric oxide regulation of cyclic di-GMP synthesis and hydrolysis in Shewanella woodyi," Biochemistry, vol. 51, no. 10, pp. 2087-2099, 2012.
[27] C. Leng, H. G. Buss, R. A. Segalman, and Z. Chen, "Surface structure and hydration of sequence-specific amphiphilic polypeptoids for antifouling/fouling release applications,"
58 Langmuir, vol. 31, no. 34, pp. 9306-9311, 2015.
[28] A. R. Statz, R. J. Meagher, A. E. Barron, and P. B. Messersmith, "New peptidomimetic polymers for antifouling surfaces," J. Am. Chem. Soc., vol. 127, no. 22, pp. 7972-7973, 2005.
[29] N. Fusetani, "Antifouling marine natural products," (in English), Nat. Prod. Rep., vol. 28, no.
2, pp. 400-410, 2011. [Online]. Available: <Go to ISI>://WOS:000286613900008.
[30] W. C. Paradas et al., "A Novel Antifouling Defense Strategy from Red Seaweed: Exocytosis and Deposition of Fatty Acid Derivatives at the Cell Wall Surface," (in English), Plant Cell Physiol., vol. 57, no. 5, pp. 1008-1019, May 2016. [Online]. Available: <Go to ISI>://WOS:000376654200014.
[31] G. V. Vimbela, S. M. Ngo, C. Fraze, L. Yang, and D. A. Stout, "Antibacterial properties and toxicity from metallic nanomaterials," International journal of nanomedicine, vol. 12, p. 3941, 2017.
[32] C. M. Kirschner and A. B. Brennan, "Bio-inspired antifouling strategies," Annu. Rev. Mater.
Res., vol. 42, pp. 211-229, 2012.
[33] L. Pocivavsek et al., "Topography-driven surface renewal," Nat. Phys., vol. 14, no. 9, pp. 948- 953, 2018, doi: 10.1038/s41567-018-0193-x.
[34] A. K. Epstein, D. Hong, P. Kim, and J. Aizenberg, "Biofilm attachment reduction on bioinspired, dynamic, micro-wrinkling surfaces," New J. Phys., vol. 15, no. 9, p. 095018, 2013.
[35] L. Pocivavsek et al., "Topography-driven surface renewal," Nat. Phys., vol. 14, no. 9, p. 948, 2018.
[36] L. Pocivavsek et al., "Active wrinkles to drive self-cleaning: A strategy for anti-thrombotic surfaces for vascular grafts," Biomaterials, vol. 192, pp. 226-234, Feb 2019, doi:
10.1016/j.biomaterials.2018.11.005.
[37] P. Shivapooja, Q. Wang, B. Orihuela, D. Rittschof, G. P. López, and X. Zhao, "Bioinspired surfaces with dynamic topography for active control of biofouling," Adv. Mater., vol. 25, no.
10, pp. 1430-1434, 2013.
[38] V. Levering, C. Cao, P. Shivapooja, H. Levinson, X. Zhao, and G. P. López, "Urinary catheter capable of repeated on-demand removal of infectious biofilms via active deformation,"
Biomaterials, vol. 77, pp. 77-86, 2016.
[39] A. Tripathi, H. Shum, and A. C. Balazs, "Fluid-driven motion of passive cilia enables the layer to expel sticky particles," Soft Matter, vol. 10, no. 9, pp. 1416-1427, 2014.
[40] H. Shum, A. Tripathi, J. M. Yeomans, and A. C. Balazs, "Active ciliated surfaces expel model swimmers," Langmuir, vol. 29, no. 41, pp. 12770-6, Oct 15 2013, doi: 10.1021/la402783x.
[41] Y. Yawata, J. Nguyen, R. Stocker, and R. Rusconi, "Microfluidic studies of biofilm formation in dynamic environments," J. Bacteriol., vol. 198, no. 19, pp. 2589-2595, 2016.
59
[42] M. E. Matherne, K. Cockerill, Y. Zhou, M. Bellamkonda, and D. L. Hu, "Mammals repel mosquitoes with their tails," J. Exp. Biol., vol. 221, no. 20, p. jeb178905, 2018.
[43] K. Böröczky, A. Wada-Katsumata, D. Batchelor, M. Zhukovskaya, and C. Schal, "Insects groom their antennae to enhance olfactory acuity," Proc. Natl. Acad. Sci., vol. 110, no. 9, pp.
3615-3620, 2013.
[44] E. G. Drucker and G. V. Lauder, "Locomotor forces on a swimming fish: three-dimensional vortex wake dynamics quantified using digital particle image velocimetry," J. Exp. Biol., vol.
202, no. 18, pp. 2393-2412, 1999.
[45] G. D. Bixler and B. Bhushan, "Rice and butterfly wing effect inspired low drag and antifouling surfaces: a review," Crit. Rev. Solid State Mater. Sci., vol. 40, no. 1, pp. 1-37, 2015.
[46] S.-J. Park et al., "Phototactic guidance of a tissue-engineered soft-robotic ray," Science, vol.
353, no. 6295, pp. 158-162, 2016.
[47] R. G. Bottom Ii, I. Borazjani, E. L. Blevins, and G. V. Lauder, "Hydrodynamics of swimming in stingrays: numerical simulations and the role of the leading-edge vortex," J. Fluid Mech., vol. 788, pp. 407-443, 2016, doi: 10.1017/jfm.2015.702.
[48] H. E. Jeong, J.-K. Lee, H. N. Kim, S. H. Moon, and K. Y. Suh, "A nontransferring dry adhesive with hierarchical polymer nanohairs," Proc. Natl. Acad. Sci., vol. 106, no. 14, pp.
5639-5644, 2009.
[49] A. Dorfmann and R. Ogden, "Magnetoelastic modelling of elastomers," Eur. J. Mech. A.
Solids, vol. 22, no. 4, pp. 497-507, 2003.
[50] I. Brigadnov and A. Dorfmann, "Mathematical modeling of magneto-sensitive elastomers,"
Int. J. Solids Struct., vol. 40, no. 18, pp. 4659-4674, 2003.
[51] D. J. Griffiths, Introduction to electrodynamics. Prentice Hall, New Jersey, 1962.
[52] J. Rychlewski, "On Hooke's law," J. Appl. Math. Mech., vol. 48, no. 3, pp. 303-314, 1984.
[53] G. Sandberg, P.-A. Wernberg, and P. Davidsson, "Fundamentals of Fluid-Structure Interaction," in Computational Aspects of Structural Acoustics and Vibration, vol. 505:
Springer, New York, 2008, pp. 23-101.
[54] E. Uddin and H. J. Sung, "Simulation of flow‐flexible body interactions with large deformation," Int. J. Numer. Methods Fluids, vol. 70, no. 9, pp. 1089-1102, 2011.
[55] F. B. Tian, H. Dai, H. Luo, J. F. Doyle, and B. Rousseau, "Fluid-structure interaction involving large deformations: 3D simulations and applications to biological systems," J.
Comput. Phys., vol. 258, pp. 451-469, Feb 1 2014, doi: 10.1016/j.jcp.2013.10.047.
[56] G. Hou, J. Wang, and A. Layton, "Numerical methods for fluid-structure interaction—a review," Commun. Comput. Phys., vol. 12, no. 2, pp. 337-377, 2012.
[57] S. Basting, A. Quaini, S. Čanić, and R. Glowinski, "Extended ALE Method for fluid–structure interaction problems with large structural displacements," J. Comput. Phys., vol. 331, pp.
60 312-336, 2017.
[58] S. Kim, W.-X. Huang, and H. J. Sung, "Constructive and destructive interaction modes between two tandem flexible flags in viscous flow," J. Fluid Mech., vol. 661, pp. 511-521, 2010.
[59] A. Seena and H. J. Sung, "Dynamic mode decomposition of turbulent cavity flows for self- sustained oscillations," Int. J. Heat Fluid Flow, vol. 32, no. 6, pp. 1098-1110, 2011.
[60] C.-H. Chang, C.-J. Tang, and C. Lin, "Vortex generation and flow pattern development after a solitary wave passing over a bottom cavity," Computers & Fluids, vol. 53, pp. 79-92, 2012.
[61] F. C. Ting and Y.-K. Kim, "Vortex generation in water waves propagating over a submerged obstacle," Coastal Engineering, vol. 24, no. 1-2, pp. 23-49, 1994.
[62] C. Berne, C. K. Ellison, A. Ducret, and Y. V. Brun, "Bacterial adhesion at the single-cell level," Nat. Rev. Microbiol., vol. 16, pp. 616-27, 2018.
[63] H. Schlichting and K. Gersten, Boundary-layer theory. Springer, New York, 2016.
[64] M. K. Kim, F. Ingremeau, A. Zhao, B. L. Bassler, and H. A. Stone, "Local and global consequences of flow on bacterial quorum sensing," Nat. Microbiol., vol. 1, p. 15005, Jan 11 2016, doi: 10.1038/nmicrobiol.2015.5.
[65] R. Hartmann et al., "Emergence of three-dimensional order and structure in growing biofilms," Nat. Phys., vol. 15, no. 3, pp. 251-256, 2018, doi: 10.1038/s41567-018-0356-9.
[66] R. Rusconi, J. S. Guasto, and R. Stocker, "Bacterial transport suppressed by fluid shear," Nat.
Phys., vol. 10, no. 3, pp. 212-217, 2014, doi: 10.1038/nphys2883.
[67] H. E. Jeong, I. Kim, P. Karam, H. J. Choi, and P. Yang, "Bacterial recognition of silicon nanowire arrays," Nano Lett., vol. 13, no. 6, pp. 2864-9, Jun 12 2013, doi: 10.1021/nl401205b.
[68] H.-H. Park et al., "Lipid-hydrogel-nanostructure hybrids as robust biofilm-resistant polymeric materials," ACS Macro Lett., vol. 8, no. 1, pp. 64-69, 2018.
[69] W. E. Stamm, "Catheter-associated urinary tract infections: epidemiology, pathogenesis, and prevention," The American journal of medicine, vol. 91, no. 3, pp. S65-S71, 1991.
61
Acknowledgements
This research was financially supported by the National Research Foundation of Korea (NRF) (2019M3C1B7025092) and approved by the Institutional Review Board (IRB) of Ulsan National Institute of Science and Technology (UNIST) (UNISTIRB-18-63-A). We express gratitude for access to the supercomputing resources of the UNIST Supercomputing Center.
I would like to express my deep gratitude to all who supported my work and contributed to this doctoral thesis.
Firstly, the deepest appreciation goes to my advisor Prof. Hoon Eui Jeong for the motivation, encouragement, and guidance in all the time of research and writing of the thesis.
I am deeply grateful to the rest of the thesis committee: Prof. Taesung Kim, Prof. Sung Youb Kim, Prof. Yoon-Kyoung Cho and Prof. Moon Kyu Kwak for offering the insightful and valuable comments and constructive criticisms.
I would also like to thank the collaborators and experts who were involved in the analysis and validation for this research: Dr. Hyeokjun Byeon, Prof. Sang Joon Lee, Dr. Jaeha Ryu, Prof. Hyung Jin Sung and Hong-Chan Joung.
I sincerely thank my labmates: Hoon Yi, Hyun-Ha Park, Minho Seong, Insol Hwang, Kahyun Sun, Sang-Hyeon Lee, Minsu Kang, Hyunwook Ko, Joosung Lee, Geonjun Choi, Jae Il Kim and Hye Jin Jang for having unforgettable years together.
Special thanks go to all my friends who have always believed and supported me and my work.
Finally, I would like to express my heartfelt gratitude to my parents, Kyungrok Ko and Misun Kang, and my brother, Hansol Ko, for continuous love and support throughout my graduate school life.