Island brushes to control adhesion of water in oil droplets on planar surfaces

Abstract

By using molecular self-assembly and polymer brush chemistry, adhesion of water droplets at solid/oil interfaces could be achieved and modulated by external triggers. Silicon wafers were hydrophobically modified with binary mixed self-assembled layers consisting of fluorinated silanes and atom transfer radical polymerisation (ATRP) initiator silanes, and subsequently grafted with responsive polymers via surface-initiated ATRP. Temperature-and pH-responsive adhesion of water in oil droplets occurred on surfaces coated with phase-separated self-assembled layers and grafted with short polymer chains. Experimental section Materials Di(ethylene glycol) methyl ether methacrylate (MEO 2 MA), poly (ethylene glycol) methyl ether methacrylate (average M n z 300)

Nanostructured Surfaces through Immobilization of Self‐Assembled Polymer Architectures Using Thiol–Ene Chemistry

“…On the fully functionalized surface, the thiol groups were covalently attached using silane chemistry. The polymeric spacer surfaces were prepared in a two‐step process: modification with 50% relative density of aminosilanes, which was achieved by mixing the functional silane with an unreactive silane in solution prior to the immobilization reaction . This reaction was followed by EDC coupling of bifunctional HOOC‐PEG‐SH (MW ≈ 3000 g mol −1 ) to the amino groups (for characterization see Figures S11–S13, Supporting Information).…”

“…The polymeric spacer surfaces were prepared in a two-step process: modification with 50% relative density of aminosilanes, which was achieved by mixing the functional silane with an unreactive silane in solution prior to the immobilization reaction. [35,36] This reaction was followed by EDC coupling of bifunctional HOOC-PEG-SH (MW ≈ 3000 g mol −1 ) to the amino groups (for characterization see Figures S11-S13, Supporting Information). Successful preparation of both types of functional surfaces was confirmed through characterization of the surfaces.…”

The Architecture of Oligonucleotide-Polycationic Brush Complexes - A Neutron Reflectometry Study

“…It is well established that weak as well as strong polyelectrolyte brushes are inherently responsive systems. Their solution morphology is strongly impacted by environmental parameters such as pH, ionic strength, temperature, and the presence of small molecules [26][27][28][29][30] . In particular, the pH, solvent and ionic strength response of weak polybase brushes such as PDMAEMA, poly(diethylaminoethyl methacrylate), their parent acrylates and copolymers, and strong polyelectrolyte brushes such as PMETAI have been extensively investigated via ellipsometry and neutron reflectometry [28,[31][32][33][34][35] .…”

Super-hydrophobic surface with switchable adhesion responsive to both temperature and pH

“…Recently, with the development of combined responsive materials and surface roughness, several superhydrophobic surfaces with switchable adhesion have been reported. [26][27][28][29][30][31][32][33][34][35] However, all of these surfaces are responsive to only one kind of stimulus, such as temperature, 28 optical 30 or electric field, 29 and this would be insufficient in many important applications with complex environments, such as biological devices and drug delivery systems, which often need the surfaces to respond to more than one stimulus simultaneously. 36 In addition, these methods are all focused on the variation of the surface to pure water, nevertheless, in some microfluidic devices and controllable separation system, the condition of water droplet such as pH, ion strength, and so on, are also very important.…”