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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.


Fabrication procedure consisting of three main steps: 1(a)–(d) Fabrication of a PDMS replica from a Si master substrate. 2(a)–(d) Taking the PDMS replica as a mold to obtain a PS/PTFE mold. 3(a) Pouring conductive PDMS on PS/PTFE master. 3(b)–(c) Removing excess material using a PDMS blade. 3(d) Pouring nonconductive PDMS atop of the uncured conductive PDMS structures. 3(e) Demolding cured condcutive and nonconductive PDMS structure.
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Figure 2: Fabrication procedure consisting of three main steps: 1(a)–(d) Fabrication of a PDMS replica from a Si master substrate. 2(a)–(d) Taking the PDMS replica as a mold to obtain a PS/PTFE mold. 3(a) Pouring conductive PDMS on PS/PTFE master. 3(b)–(c) Removing excess material using a PDMS blade. 3(d) Pouring nonconductive PDMS atop of the uncured conductive PDMS structures. 3(e) Demolding cured condcutive and nonconductive PDMS structure.

Mentions: The subsequent fabrication process allows the production of PDMS structures with very high aspect ratios. In this work, structures with a 1:10 aspect ratio have successfully been developed, but even higher ratios are feasible. The entire fabrication of PDMS structures with this process is depicted in figure 2.


Highly elastic conductive polymeric MEMS
Fabrication procedure consisting of three main steps: 1(a)–(d) Fabrication of a PDMS replica from a Si master substrate. 2(a)–(d) Taking the PDMS replica as a mold to obtain a PS/PTFE mold. 3(a) Pouring conductive PDMS on PS/PTFE master. 3(b)–(c) Removing excess material using a PDMS blade. 3(d) Pouring nonconductive PDMS atop of the uncured conductive PDMS structures. 3(e) Demolding cured condcutive and nonconductive PDMS structure.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 2: Fabrication procedure consisting of three main steps: 1(a)–(d) Fabrication of a PDMS replica from a Si master substrate. 2(a)–(d) Taking the PDMS replica as a mold to obtain a PS/PTFE mold. 3(a) Pouring conductive PDMS on PS/PTFE master. 3(b)–(c) Removing excess material using a PDMS blade. 3(d) Pouring nonconductive PDMS atop of the uncured conductive PDMS structures. 3(e) Demolding cured condcutive and nonconductive PDMS structure.
Mentions: The subsequent fabrication process allows the production of PDMS structures with very high aspect ratios. In this work, structures with a 1:10 aspect ratio have successfully been developed, but even higher ratios are feasible. The entire fabrication of PDMS structures with this process is depicted in figure 2.

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.