Precision patterning of PDMS membranes and applications

Tong, Jianhua; Simmons, Craig A.; Sun, Yu

doi:10.1088/0960-1317/18/3/037004

Cited by 39 publications

(24 citation statements)

References 17 publications

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“…This statement holds for measurements in both direction (parallel and perpendicular to the needles). The recovered values of the Young´s modulus of PDMS in the absence of fillers, (690 ± 10) kPa, calculated from both fits (exponential law and Mooney-Rivlin law) are coincident and in agreement with reported values in previous work [22][23][24][25]. The Young´s moduli of the composite in both directions, parallel and perpendicular to the needles are referred as E || and E  , and take values of (900 ± 10) and (780 ± 10) kPa, respectively, which corresponds to an elastic anisotropy of ca.…”

Section: 2b Elastic Propertiessupporting

confidence: 90%

Superparamagnetic anisotropic elastomer connectors exhibiting reversible magneto-piezoresistivity

Mietta

Jorge

Pérez

et al. 2013

Sensors and Actuators A: Physical

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An anisotropic magnetorheological composite formed by dispersions of silver-covered magnetite microparticles (Fe3O4@Ag) in polydimethylsiloxane (PDMS) displaying electrical conduction only in one preferred direction is presented. A set-up for applying and detecting electrical conduction through the composite is described and applied to characterize the behavior of the system in on-off commutation cycles. The composite is obtained by loading the polymer with relatively low concentration of fillers (5% w/w of the total weight) and curing it in the presence of a uniform magnetic field. The fillers appear in the final composite as an array of needles, i.e. pseudo-chains of particles aligned in the direction of the magnetic field. Using Fe3O4 nanoparticles (13 nm) it is possible to obtain cured composites in a superparamagnetic state, that is, without magnetic hysteresis at room temperature. Hysteresis is not found in the elastic properties either; in particular, Mullins effects (change of physical properties after the first strain-stress cycle) were not observed. No measurable transversal electrical conduction was detected (transversal resistivity larger than 62 Mohms•cm). Thus, significant electrical conductivity is present only between contact points that are exactly facing each other at both sides of the composites in the direction parallel to the needles. The I-V curves in that direction have ohmic behavior and exhibit both piezoresistance and magnetoresistance, that is, the electrical conductivity in the direction parallel to the pseudochains increases when a pressure (i.e. compressive stress) is applied at constant magnetic field and/or when a magnetic field is applied at constant pressure. The materials do not exhibit magnetoelectric or piezoresistive hysteresis. These characteristics illustrate the high potentiality of these systems in elastic connectors where electrical conduction can be varied by external mechanical or magnetic forces. List of changes following suggestions of the reviewerWe improved the language following all the suggestions of the reviewer, listed here: Table 1 Figure 7 shows the absence of significant transversal conductivity for an elastomeric connector of 2 mm thickness. Measurements were performed using the set-up shown in Figure 1.This result was observed also for samples of 1 and 3 mm thickness, which is consistent with the no variation of the resistivities (  and   ) with the sample thickness". Page 14: another sentence was rephrased: "On the other hand, no measurable current was detected between contacts that do not coincide vertically". 1) A glossary of terms is included asPage 15: "…the desired anisotropic properties, which, in this case, are stabilized by the curing of the PDMS resin".Page 15: "The fillers and the matrix appear contactless after curing."Page 15: another sentence was rephrased: "The absence of hysteresis in the elastic, piezoresistive and magnetoresistive properties can be associated to the lack of relevant adhesion between the inorganic fillers ...

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Section: 2b Elastic Propertiessupporting

confidence: 90%

Superparamagnetic anisotropic elastomer connectors exhibiting reversible magneto-piezoresistivity

Mietta

Jorge

Pérez

et al. 2013

Sensors and Actuators A: Physical

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“…Figure 3(b) shows arrays of 30 µm diameter openings with 100 µm, 200 µm, and 300 µm center-to-center distances all showing good results. This capability of creating holes in PDMS could not be achieved by the previously reported parylene lift-off based PDMS patterning technique since it would have been impossible to remove the parylene patterns from each of the holes by pealing them off [23]. …”

Section: Resultsmentioning

confidence: 99%

“…Eon et al demonstrated that PDMS can be directly patterned using oxygen plasma etching, but the slow etch rate (7 nm/min) due to silicon oxide-like layer formation on top and the rough surface after plasma etching is limiting its use [22]. Tong et al introduced a precision PDMS patterning method using a parylene C layer lift-off process that provided a relatively smooth surface [23]. In this method, PDMS was spin-coated and cured on a parylene C layer that was deposited and patterned by a low-pressure chemical vapor deposition and a RIE.…”

Section: Introductionmentioning

confidence: 99%

Micropatterning of poly(dimethylsiloxane) using a photoresist lift-off technique for selective electrical insulation of microelectrode arrays

Park¹,

Kim²,

Han³

2009

J. Micromech. Microeng.

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A poly(dimethylsiloxane) (PDMS) patterning method based on a photoresist lift-off technique to make an electrical insulation layer with selective openings is presented. The method enables creating PDMS patterns with small features and various thicknesses without any limitation in the designs and without the need for complicated processes or expensive equipments. Patterned PDMS layers were created by spin-coating liquid phase PDMS on top of a substrate having sacrificial photoresist patterns, followed by a photoresist lift-off process. The thickness of the patterned PDMS layers could be accurately controlled (6.5–24 µm) by adjusting processing parameters such as PDMS spin-coating speeds, PDMS dilution ratios, and sacrificial photoresist thicknesses. PDMS features as small as 15 µm were successfully patterned and the effects of each processing parameter on the final patterns were investigated. Electrical resistance tests between adjacent electrodes with and without the insulation layer showed that the patterned PDMS layer functions properly as an electrical insulation layer. Biocompatibility of the patterned PDMS layer was confirmed by culturing primary neuron cells on top of the layer for up to two weeks. An extensive neuronal network was successfully formed, showing that this PDMS patterning method can be applied to various biosensing microdevices. The utility of this fabrication method was further demonstrated by successfully creating a patterned electrical insulation layer on flexible substrates containing multi-electrode arrays.

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“…PDMS pre-solution was spun at 500rpm for the 30s to allow the liquid to cover the substrate uniformly and subsequently the speed was set to half of the target speed for other 30s. The final step defined as the target speed (500-6000rpm) is set for 60s to reach the desired thickness of the PDMS [21]. Four different films were prepared at four different target velocities: 500 (PDMS0.5), 1000 (PDMS1), 4000 (PDMS4) and 6000rpm (PDMS6).…”

Section: Pdms Substrates Preparationmentioning

confidence: 99%

Microstructured hybrid scaffolds for aligning neonatal rat ventricular myocytes

Sanzari

Dinelli²,

Humphrey

et al. 2019

Materials Science and Engineering: C

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In cardiac tissue engineering (TE), in vitro models are essential for the study of healthy and pathological heart tissues in order to understand the underpinning mechanisms. In this scenario, scaffolds are platforms that can realistically mimic the natural architecture of the heart, and they add biorealism to in vitro models. This paper reports a novel and robust technique to fabricate cardiovascular-mimetic scaffolds based on Parylene C and Polydimethylsiloxane (PDMS). Parylene C is employed as a mask material for inducing hybrid and nonhybrid micropatterns to the PDMS layer. Hybrid architectures present striped hydrophobic/hydrophilic surfaces, whereas non-hybrid scaffolds only corrugated topographies. Herein, we demonstrate that wavy features on PDMS can be obtained at the micro-and nanoscale and that PDMS can be integrated into the microfabrication process without changing its intrinsic physical properties. A study of the effects of these scaffolds on the growth of Neonatal Rat Ventricular Myocytes (NRVMs) cultures reveals that cell alignment occurs only for the case of hybrid architectures made of hydrophilic PDMS and hydrophobic Parylene C.

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Precision patterning of PDMS membranes and applications

Cited by 39 publications

References 17 publications

Superparamagnetic anisotropic elastomer connectors exhibiting reversible magneto-piezoresistivity

Superparamagnetic anisotropic elastomer connectors exhibiting reversible magneto-piezoresistivity

Micropatterning of poly(dimethylsiloxane) using a photoresist lift-off technique for selective electrical insulation of microelectrode arrays

Microstructured hybrid scaffolds for aligning neonatal rat ventricular myocytes

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