| 1. |
- Klintberg, Lena, et al.
(författare)
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A large stroke, high force paraffin phase transition actuator
- 2002
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Ingår i: Sensors and Actuators A-Physical. - 0924-4247 .- 1873-3069. ; 96:2-3, s. 189-195
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Tidskriftsartikel (refereegranskat)abstract
- An actuator that uses the volume expansion related to the solid-to-liquid phase transition of paraffin wax has been fabricated and evaluated. The actuator consists of a ring-shaped paraffin cavity confined by two joint silicon diaphragms with rigid centers. When the paraffin is melted, the resulting hydrostatic pressure deflects the joined rigid centers in one direction only. The magnitude of the deflection is primarily a function of the geometrical relation between the two diaphragms, giving the opportunity to tailor the behavior of the actuator in a large range. Conventional IC-processing techniques have been used to fabricate a prototype with a width of 68 mm and a thickness of 825 μm. The prototype attained a maximum deflection of ca. 90 μm. Loaded with 3 N it still exhibits a deflection of ca. 75 μm. The device can be used as a thermal switch.
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| 2. |
- Klintberg, Lena, et al.
(författare)
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A thermal microactuator made by partial impregnation of polyimide with paraffin
- 2002
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Ingår i: Journal of Micromechanics and Microengineering. - : IOP Publishing. - 0960-1317 .- 1361-6439. ; 12:6, s. 849-854
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Tidskriftsartikel (refereegranskat)abstract
- We have fabricated and tested thermal, paraffin-impregnated polyimide actuators, utilizing the large volume increase associated with the solid-to-liquid phase transition of paraffin. In the bimorph-like device, the top layer was made porous by ion track technology. Stochastically distributed pores of various lengths (95, 70, 45 and 20 µm) and various lateral coverages (5–45%) were filled with paraffin by liquid substitution or from vacuum, and sealed with epoxy. Actuators, 125 µm thick, 35 mm long and 7 mm wide, have been characterized with respect to tip deflection and load-carrying capacity with one end rigidly clamped. Loaded with 0.6 g or about ten times their own weight at their free end, about 50% of the maximum stroke (17 mm) was still attained.
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| 3. |
- Klintberg, Lena, et al.
(författare)
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A thermally activated paraffin-based actuator for gas-flow control in a satellite electrical propulsion system
- 2003
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Ingår i: Sensors and Actuators A-Physical. - 0924-4247 .- 1873-3069. ; 105:3, s. 237-246
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Tidskriftsartikel (refereegranskat)abstract
- Microstructured silicon devices consisting of three inflatable paraffin-filled, corrugated caddies suspended in springs to minimize thermal losses have been fabricated and evaluated with a valve application in mind. The large volume expansion associated with the thermally induced solid-to-liquid phase transition of paraffin is used to activate the caddies’ diaphragms. Theses components all with a thickness of 600 μm and a diameter of 39 mm, but with three different corrugations, have been fabricated with deep reactive etching (DRIE). Whereas the corrugated diaphragms could endure a deflection larger than 50 μm, only strokes of 15 μm on each side were attained when the components were activated. Together with the valve seats proposed, the investigated devices have a potential in electrical propulsion systems for satellites.
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| 4. |
- Klintberg, Lena, et al.
(författare)
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Fabrication of a paraffin actuator using hot embossing of polycarbonate
- 2003
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Ingår i: Sensors and Actuators A-Physical. - 0924-4247 .- 1873-3069. ; 103:3, s. 307-316
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Tidskriftsartikel (refereegranskat)abstract
- In this paper a fabrication process for integrating paraffin-actuated structures in polycarbonate is outlined. A paraffin-actuated membrane with a diameter of 2.5 mm, where the volume expansion of 10–15% associated with the solid-to-liquid phase transition of paraffin is utilized, has been fabricated and evaluated. Microstructures fabricated in silicon have via an electroplated nickel mould been replicated in polycarbonate by hot embossing and the resulting structures have been sealed by thermal bonding. The bonding strength was measured by a pressurizing test, and the polycarbonate surfaces were characterized with electron spectroscopy for chemical analysis (ESCA). It was found that the bond strength increased when an oxygen plasma treatment was used prior to bonding. ESCA measurements showed a corresponding increase in oxygen content on the plasma treated surfaces. This procedure also improved the wetting properties. The contact angle between paraffin and polycarbonate decreased from 10° after embossing to about 5° after plasma treatment. The fabricated actuator had a total thickness of 1 mm and the membrane deflected about 140 μm when heating the actuator above the melting point of paraffin. Paraffin wax actuators are possible to integrate in plastic structures making them promising candidates in applications such as disposable microfluidic systems where inexpensive and robust valves and pumps are needed.
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| 5. |
- Klintberg, Lena, et al.
(författare)
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Sodium hypochlorite as a developer for heavy ion tracks in polyimide
- 2001
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Ingår i: Nuclear Instruments and Methods in Physics Research Section B. - 0168-583X .- 1872-9584. ; 184:4, s. 536-543
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Tidskriftsartikel (refereegranskat)abstract
- he developing and etching of heavy ion tracks in polyimide with sodium hypochlorite have been studied to gain control over the parameters that affect the etch result. The shape of the resulting pores is a function of both alkalinity and hypochlorite content of the solution. Sodium hypochlorite decomposes during etching, and the rate constant has been determined as a function of the alkalinity at 62 °C. Polished cross-sections have been examined to determine the pore shape, and this method has shown to be a straightforward way to characterise the pores. Decreasing the alkalinity gives more cylindrical pores, but increases the decomposition rate of the hypochlorite solution and decreases the etch rate.
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| 6. |
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| 7. |
- Vallin, Örjan, et al.
(författare)
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Direct bonded quartz resonators
- 2001
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Ingår i: Proc. of the IEEE International Frequency Control Symposium, Seattle, USA, June 6-8.
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Konferensbidrag (refereegranskat)
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