title: Local Light-Induced Modification of the Inside of Microfluidic Glass Chips.
abstract: The ability to locally functionalize the surface of glass allows for myriad biomedical and chemical applications. This would be the case if the surface functionalization can be induced using light with wavelengths for which standard glass is almost transparent. To this aim, we present the first example of a photochemical modification of hydrogen-terminated glass (H-glass) with terminal alkenes. Both flat glass surfaces and the inside of glass microchannels were modified with a well-defined, covalently attached organic monolayer using a range of wavelengths, including sub-band-gap 302 nm ultraviolet light. A detailed characterization thereof was conducted by measurements of the static water contact angle, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and scanning Auger microscopy (SAM). Germanium attenuated total reflection Fourier transform infrared (GATR-FTIR) indicates that the mechanism of the surface modification proceeds via an anti-Markovnikov substitution. Reacting H-glass with 10-trifluoro-acetamide-1-decene (TFAAD) followed by basic hydrolysis affords the corresponding primary amine-terminated monolayer, enabling additional functionalization of the substrate. Furthermore, we show the successful formation of a photopatterned amine layer by the specific attachment of fluorescent nanoparticles in very discrete regions. Finally, a microchannel was photochemically patterned with a functional linker allowing for surface-directed liquid flow. These results demonstrate that H-glass can be modified with a functional tailor-made organic monolayer, has highly tunable wetting properties, and displays significant potential for further applications.
authors.affiliation: Laboratory of Organic Chemistry, Wageningen University , Dreijenplein 8, 6703 HB Wageningen, The Netherlands.|Micronit Microfluidics B.V., Colosseum 15, 7521 PV Enschede, The Netherlands.
authors.forename: Rui Rijo
authors.initials: RR
authors.lastname: Carvalho
authors.affiliation: Laboratory of Organic Chemistry, Wageningen University , Dreijenplein 8, 6703 HB Wageningen, The Netherlands.
authors.forename: Sidharam P
authors.initials: SP
authors.lastname: Pujari
authors.affiliation: Laboratory of Organic Chemistry, Wageningen University , Dreijenplein 8, 6703 HB Wageningen, The Netherlands.
authors.forename: Stefanie C
authors.initials: SC
authors.lastname: Lange
authors.affiliation: Laboratory of Organic Chemistry, Wageningen University , Dreijenplein 8, 6703 HB Wageningen, The Netherlands.
authors.forename: Rickdeb
authors.initials: R
authors.lastname: Sen
authors.affiliation: Micronit Microfluidics B.V., Colosseum 15, 7521 PV Enschede, The Netherlands.
authors.forename: Elwin Xander
authors.initials: EX
authors.lastname: Vrouwe
authors.affiliation: Laboratory of Organic Chemistry, Wageningen University , Dreijenplein 8, 6703 HB Wageningen, The Netherlands.|Department of Chemical and Materials Engineering, King Abdulaziz University , Jeddah, Saudi Arabia.
authors.forename: Han
authors.initials: H
authors.lastname: Zuilhof