Robust and Programmable Superhydrophobic Surfaces

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dc.contributor Aalto-yliopisto fi
dc.contributor Aalto University en
dc.contributor.advisor Jokinen, Ville, Dr., Aalto University, Department of Chemistry and Materials Science, Finland Hoshian, Sasha 2017-10-05T09:04:32Z 2017-10-05T09:04:32Z 2017
dc.identifier.isbn 978-952-60-7627-0 (electronic)
dc.identifier.isbn 978-952-60-7628-7 (printed)
dc.identifier.issn 1799-4942 (electronic)
dc.identifier.issn 1799-4934 (printed)
dc.identifier.issn 1799-4934 (ISSN-L)
dc.description.abstract This thesis deals with design, fabrication and characterization of robust and programmable superhydrophobic surfaces. The content is divided into two main categories. The first part is dedicated to fabrication of durable superhydrophobic surfaces and their performance characterization, including blood compatibility. The second part focuses on programmable superhydrophobic/superhydrophilic surfaces. A new fabrication process was introduced to produce durable superhydrophobic silicon surfaces, based on geometrical modification of the surface without any hydrophobic coating. The fabrication process is based on a combination of inductively coupled plasma-reactive ion etching (ICP-DRIE) and metal-assisted chemical etching (MaCE). Elimination of hydrophobic coating made the surface chemically and thermally robust, but due to use of silicon, the mechanical fragility issue remained. A biomimetic approach inspired by the exoskeleton of insects such as Armadillidium, was introduced to tackle the mechanical robustness. The new hybrid material consists of elastomeric overhang nanostructures covered by a thin layer of metal oxide. The elastomer part can bend and deform without breaking, while the hard metal oxide layer protects the surface from mechanical damage. We used atomic layer deposition (ALD) and replica moulding to produce such hybrid PDMS/titania surfaces. Our new fabrication process is based on sacrificial etching of the aluminum template and the transfer of titania film from the template to the PDMS. Subjecting the surfaces to a battery of mechanical, thermal, chemical and radiation tests demonstrated extremely durable superhydrophobicity. As an extension to replica moulding/sacrificial template process, we introduce a new way to make hydrophobic and hemophobic elastomeric tubes. The tubes showed a dramatic drag reduction for water and blood droplets compared to control tubes. A programmable superhydrophobic surface was introduced using hierarchical silicon micro and nanostructures covered by photo-switchable materials. Combination of ICP-DRIE and RIE were used to produce silicon T-shaped microstructures. Colloidal deposition was done to introduce nanoscale roughness. These structures were then conformally coated with photoactive titania using ALD. Fast and reversible transition of superhydrophobic to hydrophobic, hydrophilic and superhydrophilic state was demonstrated using UV-exposure and thermal annealing. en
dc.format.extent 77 + app. 59
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 181/2017
dc.relation.haspart [Publication 1]: Hoshian, Sasha; Jokinen, Ville; Somerkivi, Villeseveri; Lokanathan, Arcot, R.; Franssila, Sami. 2015. Robust superhydrophobic silicon without a low surface-energy hydrophobic coating. American Chemical Society. Applied Materials & Interfaces, volume 7 (1), pages 941-949. ISSN 1944-8244. DOI: 10.1021/am507584j
dc.relation.haspart [Publication 2]: Hoshian, Sasha; Jokinen, Ville; Franssila, Sami. 2016. Robust hybrid elastomer/metal-oxide superhydrophobic surfaces. Royal Society of Chemistry. Soft Matter, volume 12, issue 31, pages 6526-6535. ISSN 1744-6848. Fulltext at Aaltodoc: DOI: 10.1039/C6SM01095D
dc.relation.haspart [Publication 3]: Hoshian, Sasha; Kankuri, Esko; Jokinen, Ville; Franssila, Sami. 2017. Water and Blood Repellent Flexible Tubes. Minor revision in Scientific Reports.
dc.relation.haspart [Publication 4]: Hoshian, Sasha; Jokinen, Ville; Hjort, Klas; Ras, Robin H. A.; Franssila, Sami. 2015. Amplified and localized photoswitching of TiO2 by micro- and nanostructuring. American Chemical Society. Applied Materials & Interfaces, volume 7 (28), pages 15593-15599. ISSN 1944-8244. DOI: 10.1021/acsami.5b04309
dc.subject.other Physics en
dc.subject.other Materials science en
dc.title Robust and Programmable Superhydrophobic Surfaces en
dc.type G5 Artikkeliväitöskirja fi Kemian tekniikan korkeakoulu fi School of Chemical Technology en
dc.contributor.department Kemian ja materiaalitieteen laitos fi
dc.contributor.department Department of Chemistry and Materials Science en
dc.subject.keyword superhydrophobic en
dc.subject.keyword superhydrophilic en
dc.subject.keyword durable en
dc.subject.keyword switchable en
dc.subject.keyword restorable en
dc.identifier.urn URN:ISBN:978-952-60-7627-0
dc.type.dcmitype text en
dc.type.ontasot Doctoral dissertation (article-based) en
dc.type.ontasot Väitöskirja (artikkeli) fi
dc.contributor.supervisor Franssila, Sami, Prof., Aalto University, Department of Chemistry and Materials Science, Finland
dc.opn Levkin, Pavel A., PD Dr., Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
dc.contributor.lab Microfabrication Group (MFG) en
dc.rev Kim, Chang Jin, Prof., University of California, Los Angles (UCLA), USA
dc.rev Gardeniers, Han, Prof., University of Twente, Enschede, Netherlands 2017-10-06

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