Direct formation of high aspect ratio multiple tilted micropillar array in liquid phase PDMS by proton beam writing

• Published in: European polymer journal Vol. 69; pp. 396 - 402
• Main Authors: Huszank, Robert, Rajta, István, Cserháti, Csaba
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-08-2015
• Subjects: Arrays; Devices; Fluence; High aspect ratio; Liquid phase resist; Liquids; Micropillar arrays; PDMS; Proton beam writing; Proton beams; Resists; Silicone resins; Tilted and multiple micropillars; Tilted and multiple micropillars; Liquid phase resist; Micropillar arrays; PDMS; Proton beam writing
• ISSN: 0014-3057; 1873-1945
• DOI: 10.1016/j.eurpolymj.2015.06.023

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•High aspect ratio straight and tilted micropillars were created in PDMS polymer.•The polymer was applied in liquid form, patterned with proton beam writing method.•The pillars have smooth side walls and are stable against the capillary forces.•Structures with various tilting angle were demonstrated (±15° to 45°).•Increasing proton fluence significantly increase the Young’s modulus of the PDMS.
High aspect ratio (HAR), straight and tilted micropillars were fabricated in PDMS polymer by proton beam writing (PBW) method. The polymer was applied as a negative tone resist material, in its liquid and high viscosity form. The microstructures were created by irradiating the polymer with 2MeV focused proton beam, by which, the irradiated area became cross-linked and solid. The formed micropillars had very smooth side walls and they were stable against the capillary and adhesion forces, above a certain applied proton fluence. The rate of the solidification strongly depends on the deposited ion fluence. Furthermore, some physicochemical properties, such as elastic modulus also significantly change due to ion irradiation induced processes. This liquid PDMS resist with PBW makes the possibility to create high aspect ratio, straight or even tilted micropillar arrays with tunable properties, which can be useful in many potential applications, like lab-on-a-chip devices, high surface required applications, catalysis, biomedical applications, cell separation, and directional adhesive surfaces.