Customization of Poly(dimethylsiloxane) Stamps by Micromachining Using a Femtosecond‐Pulsed Laser
Customization of Poly(dimethylsiloxane) Stamps by Micromachining Using a Femtosecond‐Pulsed Laser
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DOI：
10.1002/adma.200390012
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发表时间：
2003-01
影响因子：
29.4
通讯作者：
D. Wolfe;J. Ashcom;J. Hwang;C. Schaffer;E. Mazur;G. M. Whitesides
中科院分区：
文献类型：
--
作者：
D. Wolfe;J. Ashcom;J. Hwang;C. Schaffer;E. Mazur;G. M. Whitesides
This work describes the use of focused, high-intensity light from a Ti:sapphire laser that generates femtosecond pulses to create topographical structure in a flat surface of poly(di-methylsiloxane) (PDMS), and the use of the PDMS surfaces patterned using this procedure for a range of purposes. PDMS patterned in surface bas-relief is the material most widely used for printing and stamping in soft lithography, [1,2] and a material widely used in microfluidic systems. [3] The bas-relief patterns required in these applications are usually fabricated by casting PDMS against a complementary bas-relief pattern in photoresist, fabricated in turn by photolithography. This process works well, but is not applicable to the preparation of PDMS stamps required for all types of problems; printing on spherical surfaces is an example. The technique described here permits the non-photolitho-graphic generation of surface topography for use in soft lithography and microfluidics; this technique has three useful characteristics: i) It generates features smaller than those generated by standard rapid-prototyping techniques based on printed transparency masks. [1,2] ii) It is applicable to fabrication on non-planar surfaces. iii) It can be used in fabrication of large-area patterns. The rough, recessed features generated by this technique are useful for applications where large surface area to volume ratios are desired, e.g., in catalysis, [7] for super-hydrophobic surfaces, [8±10] in surface-enhanced Raman scattering, [11,12] and as magnetic field concentrators. [13±15] It has the disadvantages that it is a serial process, and that the laser and positioning equipment are relatively specialized. The only requirement for the material is that it must be transparent to 800 nm light: PDMS works well, but other transparent elastomeric polymers should also work. Laser ablation is a common technique for direct writing of patterns into the surfaces of metals, semiconductors, and polymers. [16,17] Most of the techniques that have been described for laser writing work through an absorption mechanism for light that is linear in light intensity. This sort of photochemistry typically requires doping of the material with sensitizers [18±20] and/or the use of UV lasers. [21,22] We have previously described the production of stamps for microcontact printing (lCP) by ablation of a doped polymer with a diode-pumped Nd:YVO 4 laser. [20] Line widths of the features produced through this technique are ~ 5 lm. This technique, as described, is substantially less useful than rapid prototyping. Another process, developed by Hull and co-workers, used a focused ion beam (FIB) to write …
