Journal ArticleDOI
Characterization of polydimethylsiloxane (PDMS) properties for biomedical micro/nanosystems.
TLDR
PDMS surface hydrophilicity and micro-textures were generally unaffected when exposed to the different chemicals, except for micro-texture changes after immersion in potassium hydroxide and buffered hydrofluoric, nitric, sulfuric, and hydrofluic acids.Abstract:
Polydimethylsiloxane (PDMS Sylgard® 184, Dow Corning Corporation) pre-polymer was combined with increasing amounts of cross-linker (5.7, 10.0, 14.3, 21.4, and 42.9 wt.%) and designated PDMS1, PDMS2, PDMS3, PDMS4, and PDMS5, respectively. These materials were processed by spin coating and subjected to common microfabrication, micromachining, and biomedical processes: chemical immersion, oxygen plasma treatment, sterilization, and exposure to tissue culture media. The PDMS formulations were analyzed by gravimetry, goniometry, tensile testing, nanoindentation, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Spin coating of PDMS was formulation dependent with film thickness ranging from 308 μm on PDMS1 to 171 μm on PDMS5 at 200 revolutions per minute (rpm). Ultimate tensile stress (UTS) increased from 3.9 MPa (PDMS1) to 10.8 MPa (PDMS3), and then decreased down to 4.0 MPa (PDMS5). Autoclave sterilization (AS) increased the storage modulus (σ) and UTS in all formulations, with the highest increase in UTS exhibited by PDMS5 (218%). PDMS surface hydrophilicity and micro-textures were generally unaffected when exposed to the different chemicals, except for micro-texture changes after immersion in potassium hydroxide and buffered hydrofluoric, nitric, sulfuric, and hydrofluoric acids; and minimal changes in contact angle after immersion in hexane, hydrochloric acid, photoresist developer, and toluene. Oxygen plasma treatment decreased the contact angle of PDMS2 from 109∘ to 60∘. Exposure to tissue culture media resulted in increased PDMS surface element concentrations of nitrogen and oxygen.read more
Citations
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Journal ArticleDOI
Mechanical characterization of bulk Sylgard 184 for microfluidics and microengineering
TL;DR: In this article, the authors report an investigation of the variation in the mechanical properties of bulk polydimethylsiloxane (PDMS) elastomers with curing temperature, over the range 25 ◦ C to 200 ¼ C, over a range up to 40% strain and hardness of 44−54 ShA.
Journal ArticleDOI
Recent developments in PDMS surface modification for microfluidic devices
TL;DR: This review will present recent research on surface modifications of PDMS using techniques ranging from metal layer coatings and layer‐by‐layer depositions to dynamic surfactant treatments and the adsorption of amphipathic proteins.
Journal ArticleDOI
Ultra-stretchable and skin-mountable strain sensors using carbon nanotubes–Ecoflex nanocomposites
TL;DR: It is found that the carbon nanotube-silicone rubber based strain sensors possess super-stretchability and high reliability for strains as large as 500%.
Journal ArticleDOI
New materials for micro-scale sensors and actuators An engineering review
Stephen A. Wilson,Renaud Jourdain,Qi Zhang,Robert A. Dorey,Christopher R. Bowen,Magnus Willander,Qamar Ul Wahab,Safaa Al-Hilli,Omer Nur,Eckhard Quandt,Christer Johansson,E. Pagounis,Manfred Kohl,Jovan Matovic,Björn Samel,Wouter van der Wijngaart,Edwin Jager,Daniel O Carlsson,Zoran Djinovic,Michael Wegener,Carmen Moldovan,Rodica Iosub,E. Abad,Michael Wendlandt,Cristina Rusu,Katrin Persson +25 more
TL;DR: In this paper, a detailed overview of developments in transducer materials technology relating to their current and future applications in micro-scale devices is provided. And a short discussion of structural polymers that are extending the range of micro-fabrication techniques available to designers and production engineers beyond the limitations of silicon fabrication technology is presented.
Journal ArticleDOI
PDMS with designer functionalities—Properties, modifications strategies, and applications
TL;DR: In this article, a review of surface modifications of PDMS, inducing properties such as hydrophilicity, electrical conductivity, anti-fouling, energy harvesting, and energy storage (supercapacitors) are discussed.
References
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Journal ArticleDOI
Rapid prototyping of microfluidic systems in poly(dimethylsiloxane)
TL;DR: A procedure that makes it possible to design and fabricate microfluidic systems in an elastomeric material poly(dimethylsiloxane) (PDMS) in less than 24 h by fabricating a miniaturized capillary electrophoresis system is described.
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Journal ArticleDOI
Fabrication of microfluidic systems in poly(dimethylsiloxane)
J.C. McDonald,David C. Duffy,Janelle R. Anderson,Daniel T. Chiu,Hongkai Wu,Olivier Schueller,George M. Whitesides +6 more
TL;DR: Fabrication of microfluidic devices in poly(dimethylsiloxane) (PDMS) by soft lithography provides faster, less expensive routes to devices that handle aqueous solutions.
Journal ArticleDOI
Soft Lithography in Biology and Biochemistry
TL;DR: Soft lithography offers the ability to control the molecular structure of surfaces and to pattern the complex molecules relevant to biology, to fabricate channel structures appropriate for microfluidics, and topattern and manipulate cells.