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Programmable and Responsive Superhydrophobic Surfaces

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dc.contributor Aalto-yliopisto fi
dc.contributor Aalto University en
dc.contributor.advisor Franssila, Sami, Prof., Aalto University, Finland
dc.contributor.author Al-Azawi, Anas
dc.date.accessioned 2021-02-17T10:00:10Z
dc.date.available 2021-02-17T10:00:10Z
dc.date.issued 2021
dc.identifier.isbn 978-952-64-0271-0 (electronic)
dc.identifier.isbn 978-952-64-0270-3 (printed)
dc.identifier.issn 1799-4942 (electronic)
dc.identifier.issn 1799-4934 (printed)
dc.identifier.issn 1799-4934 (ISSN-L)
dc.identifier.uri https://aaltodoc.aalto.fi/handle/123456789/102698
dc.description Defnse is held on 12.3.2021 12:00 – 16:00 via remote technology (Zoom), https://aalto.zoom.us/j/61326769947
dc.description.abstract Progress in the field of superhydrophobic surfaces requires precise characterization techniques and synthesis of surfaces that exhibit robust non-wettability. In this thesis, microfabrication techniques are used to produce static as well as bioinspired responsive superhydrophobic structures. In addition, transverse droplet oscillations are implemented to accurately evaluate superhydrophobicity of micropillared surfaces. Variations in surface properties that influence the degree of superhydrophobicity were successfully probed by relating friction and viscous dissipation of dynamic droplets to pattern density and chemical coating. Additionally, controlling the normal force exerted on the water-based ferrofluid droplet allows the measurement of impalement pressure necessary to induce wetting transition for a droplet in motion. A new fabrication process was introduced for rapid prototyping of cilia-inspired magnetic micropillars. The fabricated array of sub-10 µm diameter pillars are based on polydimethylsiloxane (PDMS) loaded with carbonyl iron particles (CIP). Lubricating in silicone oil allowed controlled droplet motion at the sub-mm scale facilitated by fast actuation and superhydrophobicity of the oil infused PDMS magnetic micropillars. Lack of mechanical stability due to flexibility of the high aspect ratio PDMS micropillars restricted the application of the array to liquid media only. Thiol-ene based magnetic micropillar arrays were introduced to address the stability issue of the high-aspect ratio micropillars. The remarkable properties of thiol-ene including tunability of surface and mechanical properties allowed topography modification of the magnetic micropillars using photo-induced thiol-ene click coupling. Decorating the surface of the high aspect ratio thiol-ene micropillars with polyvinyltrimethoxysilane (PVTMS) colloidal micro- and nanoparticles enhanced the mechanical stability of the flexible micropillars without compromising powerful bending actuation. This allowed actuation of the micropillar arrays in air as well as in liquid media. The magnetic micropillars were rendered superhydrophobic by grafting hydrophobic self-assemnled monolayer onto the PVTMS micro- and nanoparticles that are covalently bonded to the surface. This enabled directed water droplet motion by repetitive bending and recovery of the micropillars. Combining mechanical stability with robust superhydrophobicity can lead to numerous practical applications of cilia-inspired thiol-ene magnetic micropillars. en
dc.format.extent 108 + app. 32
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher Aalto University en
dc.publisher Aalto-yliopisto fi
dc.relation.ispartofseries Aalto University publication series DOCTORAL DISSERTATIONS en
dc.relation.ispartofseries 19/2021
dc.relation.haspart [Publication 1]: Al-Azawi, Anas; Latikka, Mika; Jokinen, Ville; Franssila, Sami; Ras, Robin A. 2017. Friction and Wetting Transitions of Magnetic Droplets on Micropillared Superhydrophobic Surfaces. Small, 13, 38, 1700860. Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-201806183316.DOI: 10.1002/smll.201700860
dc.relation.haspart [Publication 2]: Al-Azawi, Anas; Hörenz, Christoph; Tupasela, Topi; Ikkala, Olli; Jokinen, Ville; Franssila, Sami; Ras, Robin. H. A. 2020. Slippery and Magnetically Responsive Micropillared Surfaces for Manipulation of Droplets and Beads. AIP Advances, 10, 8, 085021. Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-202009185444. DOI: 10.1063/5.0012852
dc.relation.haspart [Publication 3]: Al-Azawi, Anas; Cenev, Zoran; Tupasela, Topi; Peng, Bo; Ikkala, Olli; Zhou, Quan; Jokinen, Ville; Franssila, Sami; Ras, Robin. H. A. 2020. Tunable and Magnetic Thiolene Micropillar Arrays. Macromolecular Rapid Communications, 41, 2, 1900522. Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-202001021161. DOI: 10.1002/marc.201900522
dc.subject.other Physics en
dc.title Programmable and Responsive Superhydrophobic Surfaces en
dc.type G5 Artikkeliväitöskirja fi
dc.contributor.school Perustieteiden korkeakoulu fi
dc.contributor.school School of Science en
dc.contributor.department Teknillisen fysiikan laitos fi
dc.contributor.department Department of Applied Physics en
dc.subject.keyword superhydrophobicity en
dc.subject.keyword wetting transition en
dc.subject.keyword magnetic pillars en
dc.subject.keyword thiol-ene elastomer en
dc.subject.keyword droplet manipulation en
dc.identifier.urn URN:ISBN:978-952-64-0271-0
dc.type.dcmitype text en
dc.type.ontasot Doctoral dissertation (article-based) en
dc.type.ontasot Väitöskirja (artikkeli) fi
dc.contributor.supervisor Ras, Robin, Prof., Aalto University, Department of Applied Physics, Finland
dc.opn Taboryski, Rafael, Prof., DTU Technical University of Denmark, Denmark
dc.contributor.lab Soft Matter and Wetting en
dc.rev van der Wijngaart, Wouter, Prof., KTH Royal Institute of Technology, Sweden
dc.rev Taboryski, Rafael, Prof., DTU Technical University of Denmark, Denmark
dc.date.defence 2021-03-12
local.aalto.acrisexportstatus checked 2021-03-19_1447
local.aalto.infra OtaNano - Aalto Nanofab/Micronova
local.aalto.infra OtaNano - Nanomicroscopy Center
local.aalto.formfolder 2021_02_16_klo_13_58
local.aalto.archive yes

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