Polymer blend lithography: A versatile method to fabricate nanopatterned self-assembled monolayers

Abstract

SummaryA rapid and cost-effective lithographic method, polymer blend lithography (PBL), is reported to produce patterned self-assembled monolayers (SAM) on solid substrates featuring two or three different chemical functionalities. For the pattern generation we use the phase separation of two immiscible polymers in a blend solution during a spin-coating process. By controlling the spin-coating parameters and conditions, including the ambient atmosphere (humidity), the molar mass of the polystyrene (PS) and poly(methyl methacrylate) (PMMA), and the mass ratio between the two polymers in the blend solution, the formation of a purely lateral morphology (PS islands standing on the substrate while isolated in the PMMA matrix) can be reproducibly induced. Either of the formed phases (PS or PMMA) can be selectively dissolved afterwards, and the remaining phase can be used as a lift-off mask for the formation of a nanopatterned functional silane monolayer. This “monolayer copy” of the polymer phase morphology has a topographic contrast of about 1.3 nm. A demonstration of tuning of the PS island diameter is given by changing the molar mass of PS. Moreover, polymer blend lithography can provide the possibility of fabricating a surface with three different chemical components: This is demonstrated by inducing breath figures (evaporated condensed entity) at higher humidity during the spin-coating process. Here we demonstrate the formation of a lateral pattern consisting of regions covered with 1H,1H,2H,2H-perfluorodecyltrichlorosilane (FDTS) and (3-aminopropyl)triethoxysilane (APTES), and at the same time featuring regions of bare SiOx. The patterning process could be applied even on meter-sized substrates with various functional SAM molecules, making this process suitable for the rapid preparation of quasi two-dimensional nanopatterned functional substrates, e.g., for the template-controlled growth of ZnO nanostructures [1].

Effect of immersion temperature on structure of the self-assembled monolayer of 1,2-diphenyldiselenide on gold surface

“…Fundamental characteristics of film formation, structure, and properties of self-assembled monolayers (SAMs) of organothiol molecules with aliphatic [1e11] backbones on metal surfaces, in particular on Au(111), have attracted significant attention because of their applications in molecular technologies [12], biosensorics [13e15], electrochemistry [16,17], lithography [18,19], and lubrication [20]. Subsequently, aromatic SAMs have also moved into the focus of interest [21e31] because their remarkable electronic properties that offer potential applications in a variety of fields such as in molecular electronics [32e34] and electronic interfaces [35,36].…”

Dispersion of organophilic Ag nanoparticles in PS-PMMA blends

“…The incorporation of the Ag nanoparticles into the binary polymer blend system causes the disappearance of pits; instead, surface bumps are developed. The light bumps may refer to PS-rich domains [6]. The size of surface feature is reduced from 4.5 (pits) to 0.4 (bumps) mm.…”

“…These blends have been intensively studied over the past two decades and allow the formation of complex layered or lateral micro-or nanoscale structures [5]. For instance, Huang et al prepared a spin-coat film of PS-PMMA with a pitted surface morphology [6]. The continuous PMMA phase was selectively dissolved and the remaining PS pits were used as a lift-off mask for the formation of a nanopatterned functional silane monolayer.…”

Template-controlled mineralization: Determining film granularity and structure by surface functionality patterns

“…These islands were then back-filled by exposure to the vapor of 3-(aminopropyltriethoxy)-silane (Sigma-Aldrich). Further details and important parameters of the polymer-blend lithography process are described in [32]. The resulting pattern, consisting of amino-functionalized islands in a Teflon-like matrix (Figure 1b-d), was used as a template for the mineralization.…”