Research on the cast molding process for high quality PDMS molds

Ye, Xiangdong; Li, Hongzhong; Ding, Yucheng; Li, Hansong; Lu, Bingheng

doi:10.1016/j.mee.2008.10.011

Cited by 70 publications

(49 citation statements)

References 14 publications

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“…The theoretical extent of elongation depends on the type of PDMS and the way in which it is prepared. [35,36] In principle, PDMS can be stretched beyond 40% strain, but it is likely that the antennas failed prematurely because of small defects at the surface of the PDMS that focused the applied stress. The antennas typically failed in regions of the PDMS that had been compromised or cut during fabrication.…”

Section: Resultsmentioning

confidence: 99%

Reversibly Deformable and Mechanically Tunable Fluidic Antennas

Thelen

Qusba

et al. 2009

Adv Funct Materials

527

399

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This paper describes the fabrication and characterization of fluidic dipole antennas that are reconfigurable, reversibly deformable, and mechanically tunable. The antennas consist of a fluid metal alloy injected into microfluidic channels comprising a silicone elastomer. By employing soft lithographic, rapid prototyping methods, the fluidic antennas are easier to fabricate than conventional copper antennas. The fluidic dipole radiates with ≈90% efficiency over a broad frequency range (1910–1990 MHz), which is equivalent to the expected efficiency for a similar dipole with solid metallic elements such as copper. The metal, eutectic gallium indium (EGaIn), is a low‐viscosity liquid at room temperature and possesses a thin oxide skin that provides mechanical stability to the fluid within the elastomeric channels. Because the conductive element of the antenna is a fluid, the mechanical properties and shape of the antenna are defined by the elastomeric channels, which are composed of polydimethylsiloxane (PDMS). The antennas can withstand mechanical deformation (stretching, bending, rolling, and twisting) and return to their original state after removal of an applied stress. The ability of the fluid metal to flow during deformation of the PDMS ensures electrical continuity. The shape and thus, the function of the antenna, is reconfigurable. The resonant frequency can be tuned mechanically by elongating the antenna via stretching without any hysteresis during strain relaxation, and the measured resonant frequency as a function of strain shows excellent agreement (±0.1–0.3% error) with that predicted by theoretical finite element modeling. The antennas are therefore sensors of strain. The fluid metal also facilitates self‐healing in response to sharp cuts through the antenna.

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Section: Resultsmentioning

confidence: 99%

Reversibly Deformable and Mechanically Tunable Fluidic Antennas

Thelen

Qusba

et al. 2009

Adv Funct Materials

527

399

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“…The master template used for cast molding consists of a layer of positive resist and a silicon substrate, and the master patterns are defined in the resist by a high resolution electron beam lithography system, and the casting material is PDMS (ESSIL 291) from Axson Corporation. The whole cast molding process is similar to our previous work [17].…”

Section: Experiments and Discussionmentioning

confidence: 99%

“…In 1999, Chiang et al [16] investigated castable materials and mold sticking properties, resolution of pattern transfer, and effects of surface roughness and surface wettability. In our previous work, effects of vacuum degree and the curing temperature on the quality of PDMS mold were studied; and the process was optimized to obtain PDMS molds with high fidelity and improved physical properties [17].…”

Section: Introductionmentioning

confidence: 99%

Research on the Forming Mechanism of Micro/Nano Features during the Cast Molding Process

Duan

Ding

2011

Nano-Micro Lett.

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Abstract:Cast molding process has provided a reliable, simple and cost-effective way to fabricate micro structures since decades ago. In order to obtain structures with fine, dense and deep nano-size features by cast molding, it is necessary to study the forming mechanism in the process. In this paper, based on major steps of cast molding, filling models of liquid are established and solved; and the forming mechanism of liquid is revealed. Moreover, the scale effect between the liquid and the cavity on the filling velocity of liquid is studied. It is also interesting to find out that the wettability of liquid on the cavity may be changed from wetting to dewetting depends on the pressure difference. Finally, we experimentally verify some of our modeling results on the flowing and filling state of the liquid during the cast molding process.

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“…In this case, Soft UV-NIL is useful thanks to the use of a flexible stamp which can be conforming to the shape of the surface. A common polymer material used as flexible stamp is poly(diméthylsiloxane) (PDMS) in early works [15][16][17][18][19] for its interesting physical properties such as flexibility, elasticity, low surface energy, and UV-transparency.…”

Section: Introductionmentioning

confidence: 99%