title: Comparative study of solution-phase and vapor-phase deposition of aminosilanes on silicon dioxide surfaces.
abstract: The uniformity of aminosilane layers typically used for the modification of hydroxyl bearing surfaces such as silicon dioxide is critical for a wide variety of applications, including biosensors. However, in spite of many studies that have been undertaken on surface silanization, there remains a paucity of easy-to-implement deposition methods reproducibly yielding smooth aminosilane monolayers. In this study, solution- and vapor-phase deposition methods for three aminoalkoxysilanes differing in the number of reactive groups (3-aminopropyl triethoxysilane (APTES), 3-aminopropyl methyl diethoxysilane (APMDES) and 3-aminopropyl dimethyl ethoxysilane (APDMES)) were assessed with the aim of identifying methods that yield highly uniform and reproducible silane layers that are resistant to minor procedural variations. Silane film quality was characterized based on measured thickness, hydrophilicity and surface roughness. Additionally, hydrolytic stability of the films was assessed via these thickness and contact angle values following desorption in water. We found that two simple solution-phase methods, an aqueous deposition of APTES and a toluene based deposition of APDMES, yielded high quality silane layers that exhibit comparable characteristics to those deposited via vapor-phase methods.
authors.affiliation: Department of Physics and Astronomy, University of Rochester, Rochester, NY, USA.
authors.forename: Amrita R
authors.initials: AR
authors.lastname: Yadav
authors.affiliation: Department of Biomedical Engineering, University of Rochester, Rochester, NY, USA.
authors.forename: Rashmi
authors.initials: R
authors.lastname: Sriram
authors.affiliation: Adarza Biosystems, Inc., West Henrietta, NY, USA.
authors.forename: Jared A
authors.initials: JA
authors.lastname: Carter
authors.affiliation: Department of Biomedical Engineering, University of Rochester, Rochester, NY, USA; Department of Dermatology, University of Rochester, Rochester, NY, USA; Department of Biophysics and Biochemistry, University of Rochester, Rochester, NY, USA. Electronic address: Benjamin_miller@urmc.rochester.edu.
authors.forename: Benjamin L
authors.initials: BL
authors.lastname: Miller
mesh_terms: D000327:Adsorption; D020099:Coated Materials, Biocompatible / Q000138:chemical synthesis*; D005740:Gases / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D008422:Materials Testing; D044367:Phase Transition; D012821:Silanes / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D012996:Solutions; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
chemical_list: D020099:Coated Materials, Biocompatible; D005740:Gases; D012821:Silanes; D012996:Solutions; D014867:Water; D012822:Silicon Dioxide
keywords: Aminosilane; Monolayer; Silicon dioxide functionalization