Self‐Aligned Micropatterns of Bifunctional Polymer Surfaces with Independent Chemical and Topographical Contrast

Abstract

Bifunctional surfaces are micropatterned using a self-aligned, dual-purpose lithographic mask and pairs of conformally deposited iCVD polymers. A first layer is deposited, then physically masked and etched in oxygen plasma. A second layer is deposited with the mask still in place. Lift-off reveals the micropatterned surface. The thicknesses of the two layers are independently controlled so that the resultant surface displays both chemical and topographical contrast. The patterning scheme is independent of the polymers used and order of deposition. We use this scheme to create surfaces that spatially confine microcondensation, as well as chemical functionality. We also demonstrate microwells whose depth can be altered in response to a water stimulus.

25th Anniversary Article: CVD Polymers: A New Paradigm for Surface Modifi cation and Device Fabrication

“…This method is independent of the chemical functionality of the iCVD film, allowing for easy exchange of responsive iCVD polymers for device applications. Fabrication of bifunctional surfaces has been demonstrated using a self‐aligned, dual‐purpose lithographic mask (Figure 12d) 128. The resulting surfaces exhibited chemical and topological contrast and were used to achieve confinement of water droplets during microcondensation.…”

Vapor Deposition of Fluoropolymer Surfaces

“…The grafted film was also oleophobic, having an advancing contact angle with mineral oil of 120 • [49]. Bifunctional surfaces displaying areas of hydrophobic iCVD p(PFDA) next to hydrophilic regions composed of iCVD hydrogel, polyhydroxyethylmethacrylate, p(HEMA) ( Table 7.3), were patterned down to ∼7 μm resolution using transmission electron microscope grids as lift-off masks, allowing control over microcondensation [63]. Patterning by colloidal lithography of grafted iCVD p(PFDA) resulted in hexagonally packed bowl structures 1 μm in diameter [64].…”

CVD of polymeric thin films: applications in sensors, biotechnology, microelectronics/organic electronics, microfluidics, MEMS, composites and membranes

“…TEM grids that were used as masks were either placed directly on the hydrophilic substrates, followed by the deposition of a hydrophobic film, or they were placed on hydrophobic films, followed plasma etching to remove the films in the open areas. TEM grids were also used as masks during iCVD of bifunctional polymer surfaces [67]. Placing the mask on a coated substrate and subsequent etching and coating led to bifunctional surfaces with alternating hydrophilic and hydrophobic regions.…”