Limits...
Highly elastic conductive polymeric MEMS

View Article: PubMed Central - PubMed

ABSTRACT

Polymeric structures with integrated, functional microelectrical mechanical systems (MEMS) elements are increasingly important in various applications such as biomedical systems or wearable smart devices. These applications require highly flexible and elastic polymers with good conductivity, which can be embedded into a matrix that undergoes large deformations. Conductive polydimethylsiloxane (PDMS) is a suitable candidate but is still challenging to fabricate. Conductivity is achieved by filling a nonconductive PDMS matrix with conductive particles. In this work, we present an approach that uses new mixing techniques to fabricate conductive PDMS with different fillers such as carbon black, silver particles, and multiwalled carbon nanotubes. Additionally, the electrical properties of all three composites are examined under continuous mechanical stress. Furthermore, we present a novel, low-cost, simple three-step molding process that transfers a micro patterned silicon master into a polystyrene (PS) polytetrafluoroethylene (PTFE) replica with improved release features. This PS/PTFE mold is used for subsequent structuring of conductive PDMS with high accuracy. The non sticking characteristics enable the fabrication of delicate structures using a very soft PDMS, which is usually hard to release from conventional molds. Moreover, the process can also be applied to polyurethanes and various other material combinations.

No MeSH data available.


Related in: MedlinePlus

(left) Optical microscope image of a PS/PTFE mold after detachment. The smallest features have a size 40 μm. (right) SEM image of a PS/PTFE mold.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC5036488&req=5

Figure 3: (left) Optical microscope image of a PS/PTFE mold after detachment. The smallest features have a size 40 μm. (right) SEM image of a PS/PTFE mold.

Mentions: After completion of baking step 5, the newly created mold can be detached from the PDMS frame by applying light pressure on the back of the frame. The frame with the PDMS replica of the silicon master can be reused for further fabrication of PS/PTFE molds. Figure 3 shows an optical and a scanning electron microscopic (SEM) image of a PS/PTFE mold. In the SEM image, one can see that the upper part of the side wall is slightly rougher than the lower part as a result of the DRIE process.


Highly elastic conductive polymeric MEMS
(left) Optical microscope image of a PS/PTFE mold after detachment. The smallest features have a size 40 μm. (right) SEM image of a PS/PTFE mold.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5036488&req=5

Figure 3: (left) Optical microscope image of a PS/PTFE mold after detachment. The smallest features have a size 40 μm. (right) SEM image of a PS/PTFE mold.
Mentions: After completion of baking step 5, the newly created mold can be detached from the PDMS frame by applying light pressure on the back of the frame. The frame with the PDMS replica of the silicon master can be reused for further fabrication of PS/PTFE molds. Figure 3 shows an optical and a scanning electron microscopic (SEM) image of a PS/PTFE mold. In the SEM image, one can see that the upper part of the side wall is slightly rougher than the lower part as a result of the DRIE process.

View Article: PubMed Central - PubMed

ABSTRACT

Polymeric structures with integrated, functional microelectrical mechanical systems (MEMS) elements are increasingly important in various applications such as biomedical systems or wearable smart devices. These applications require highly flexible and elastic polymers with good conductivity, which can be embedded into a matrix that undergoes large deformations. Conductive polydimethylsiloxane (PDMS) is a suitable candidate but is still challenging to fabricate. Conductivity is achieved by filling a nonconductive PDMS matrix with conductive particles. In this work, we present an approach that uses new mixing techniques to fabricate conductive PDMS with different fillers such as carbon black, silver particles, and multiwalled carbon nanotubes. Additionally, the electrical properties of all three composites are examined under continuous mechanical stress. Furthermore, we present a novel, low-cost, simple three-step molding process that transfers a micro patterned silicon master into a polystyrene (PS) polytetrafluoroethylene (PTFE) replica with improved release features. This PS/PTFE mold is used for subsequent structuring of conductive PDMS with high accuracy. The non sticking characteristics enable the fabrication of delicate structures using a very soft PDMS, which is usually hard to release from conventional molds. Moreover, the process can also be applied to polyurethanes and various other material combinations.

No MeSH data available.


Related in: MedlinePlus