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Fabrication of high sensitivity carbon microcoil pressure sensors.

Su CC, Li CH, Chang NK, Gao F, Chang SH - Sensors (Basel) (2012)

Bottom Line: This work demonstrates a highly sensitive pressure sensor that was fabricated using carbon microcoils (CMCs) and polydimethylsiloxane (PDMS).The pressure sensor has a sandwiched structure, in which the as-grown CMCs were inserted between two PDMS layers.The pressure sensor exhibits piezo-resistivity changes in response to mechanical loading using a load cell system.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, National Taiwan University, Taipei 10617, Taiwan. r92522629@ntu.edu.tw

ABSTRACT
This work demonstrates a highly sensitive pressure sensor that was fabricated using carbon microcoils (CMCs) and polydimethylsiloxane (PDMS). CMCs were grown by chemical vapor deposition using various ratios of Fe-Sn catalytic solution. The pressure sensor has a sandwiched structure, in which the as-grown CMCs were inserted between two PDMS layers. The pressure sensor exhibits piezo-resistivity changes in response to mechanical loading using a load cell system. The yields of the growth of CMCs at a catalyst proportion of Fe:Sn = 95:5 reach 95%. Experimental results show that the sensor achieves a high sensitivity of 0.93%/kPa from the CMC yield of 95%. The sensitivity of the pressure sensor increases with increasing yield of CMCs. The demonstrated pressure sensor shows the advantage of high sensitivity and is suitable for mass production.

No MeSH data available.


Related in: MedlinePlus

Fabrication process of CMC pressure sensor. (a) CMCs and CNFs were grown on SiO2 by CVD; (b) CMCs and CNFs were transferred on PDMS; (c) Ag glue was coated on both edges of the sample as electrode; (d) PDMS was coated on the Ag electrode to complete the CMC pressure sensor.
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f1-sensors-12-10034: Fabrication process of CMC pressure sensor. (a) CMCs and CNFs were grown on SiO2 by CVD; (b) CMCs and CNFs were transferred on PDMS; (c) Ag glue was coated on both edges of the sample as electrode; (d) PDMS was coated on the Ag electrode to complete the CMC pressure sensor.

Mentions: The fabrication process of the flexible pressure sensor is shown in Figure 1. The CMCs/CNFs were grown on silicon oxide film with dimensions of 10 × 10 mm2 by chemical vapor deposition (CVD) at 700 °C using ratios of Fe:Sn catalysts ranging from 80:20 to 97:3, as shown in Figure 1(a). A thickness of silicon oxide film of 500 nm was pre-deposited on 4 in silicon wafer (100) by a low-pressure chemical vapor deposition method. The powder catalyst for the CMCs grown herein was prepared by mixing Fe acetate and Sn acetate in Fe:Sn ratios = 80:20 to 97:3 in ethanol, wherein the molarity of Fe-Sn was 0.6 M. The substrate, a coating of Fe:Sn catalyst, was inserted into a quartz tube furnace at 450 °C in air for 30 min. Finally, the as-annealed sample was heated in a 1-inch quartz tube furnace at 700 °C under a 600 sccm flow of Ar gas. At 700 °C, C2H2 gas was supplied as the carbon source at a flow rate of 5 sccm for 15 min in order to grow CMCs. The PDMS was dropped on as-grown CMCs/CNFs in a cast to control the thickness of the PDMS layer. Simultaneously, the samples were placed in a low pressure chamber to eliminate the micro-bubbles inside the PDMS. After the PDMS was dried, both the PDMS and CMCs/CNFs were peeled off, as shown in Figure 1(b). Ag glue was coated on both edges of the samples as electrode (Figure 1(c)). When the Ag glue was dry, the top layer of PDMS was coated on CMCs/CNFs to complete the sensor, as shown in Figure 1(d). The dimensions of the pressure sensor in this work were 10 × 10 × 1 mm. A scanning electron microscope (SEM JEOL-6390) was used to examine the results of CMCs/CNFs. In addition, to evaluate the pressure sensing of the CMCs/CNFs pressure sensor, a load cell and multimeter were used to collect sensitivity measurements.


Fabrication of high sensitivity carbon microcoil pressure sensors.

Su CC, Li CH, Chang NK, Gao F, Chang SH - Sensors (Basel) (2012)

Fabrication process of CMC pressure sensor. (a) CMCs and CNFs were grown on SiO2 by CVD; (b) CMCs and CNFs were transferred on PDMS; (c) Ag glue was coated on both edges of the sample as electrode; (d) PDMS was coated on the Ag electrode to complete the CMC pressure sensor.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3472814&req=5

f1-sensors-12-10034: Fabrication process of CMC pressure sensor. (a) CMCs and CNFs were grown on SiO2 by CVD; (b) CMCs and CNFs were transferred on PDMS; (c) Ag glue was coated on both edges of the sample as electrode; (d) PDMS was coated on the Ag electrode to complete the CMC pressure sensor.
Mentions: The fabrication process of the flexible pressure sensor is shown in Figure 1. The CMCs/CNFs were grown on silicon oxide film with dimensions of 10 × 10 mm2 by chemical vapor deposition (CVD) at 700 °C using ratios of Fe:Sn catalysts ranging from 80:20 to 97:3, as shown in Figure 1(a). A thickness of silicon oxide film of 500 nm was pre-deposited on 4 in silicon wafer (100) by a low-pressure chemical vapor deposition method. The powder catalyst for the CMCs grown herein was prepared by mixing Fe acetate and Sn acetate in Fe:Sn ratios = 80:20 to 97:3 in ethanol, wherein the molarity of Fe-Sn was 0.6 M. The substrate, a coating of Fe:Sn catalyst, was inserted into a quartz tube furnace at 450 °C in air for 30 min. Finally, the as-annealed sample was heated in a 1-inch quartz tube furnace at 700 °C under a 600 sccm flow of Ar gas. At 700 °C, C2H2 gas was supplied as the carbon source at a flow rate of 5 sccm for 15 min in order to grow CMCs. The PDMS was dropped on as-grown CMCs/CNFs in a cast to control the thickness of the PDMS layer. Simultaneously, the samples were placed in a low pressure chamber to eliminate the micro-bubbles inside the PDMS. After the PDMS was dried, both the PDMS and CMCs/CNFs were peeled off, as shown in Figure 1(b). Ag glue was coated on both edges of the samples as electrode (Figure 1(c)). When the Ag glue was dry, the top layer of PDMS was coated on CMCs/CNFs to complete the sensor, as shown in Figure 1(d). The dimensions of the pressure sensor in this work were 10 × 10 × 1 mm. A scanning electron microscope (SEM JEOL-6390) was used to examine the results of CMCs/CNFs. In addition, to evaluate the pressure sensing of the CMCs/CNFs pressure sensor, a load cell and multimeter were used to collect sensitivity measurements.

Bottom Line: This work demonstrates a highly sensitive pressure sensor that was fabricated using carbon microcoils (CMCs) and polydimethylsiloxane (PDMS).The pressure sensor has a sandwiched structure, in which the as-grown CMCs were inserted between two PDMS layers.The pressure sensor exhibits piezo-resistivity changes in response to mechanical loading using a load cell system.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, National Taiwan University, Taipei 10617, Taiwan. r92522629@ntu.edu.tw

ABSTRACT
This work demonstrates a highly sensitive pressure sensor that was fabricated using carbon microcoils (CMCs) and polydimethylsiloxane (PDMS). CMCs were grown by chemical vapor deposition using various ratios of Fe-Sn catalytic solution. The pressure sensor has a sandwiched structure, in which the as-grown CMCs were inserted between two PDMS layers. The pressure sensor exhibits piezo-resistivity changes in response to mechanical loading using a load cell system. The yields of the growth of CMCs at a catalyst proportion of Fe:Sn = 95:5 reach 95%. Experimental results show that the sensor achieves a high sensitivity of 0.93%/kPa from the CMC yield of 95%. The sensitivity of the pressure sensor increases with increasing yield of CMCs. The demonstrated pressure sensor shows the advantage of high sensitivity and is suitable for mass production.

No MeSH data available.


Related in: MedlinePlus