Extracting uncrosslinked material from low modulus sylgard 184 and the effect on mechanical properties

Glover, Justin D.; McLaughlin, Colbi E.; McFarland, Mary K.; Pham, Jonathan T.

doi:10.1002/pol.20190032

Cited by 46 publications

(52 citation statements)

References 60 publications

(86 reference statements)

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“…As expected, the Hertzian contact model also provided a poor fit to the contact radius and indentation depth that we measured experimentally. Due to the large difference in elastic modulus between 30:1 Sylgard-184 and both of the polymers we studied, we calculated Hertzian contact using reduced elastic modulus, plane-strain modulus, and PDMS modulus alone for a range of 100 kPa − 245 kPa found in the literature [ 57 , 58 ]. The resulting Hertzian contact radius never exceeded less than half of our measured value and indentation depth was even less accurate.…”

Section: Resultsmentioning

confidence: 99%

Survival of polymeric microstructures subjected to interrogatory touch

et al. 2021

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Polymeric arrays of microrelief structures have a range of potential applications. For example, to influence wettability, to act as biologically inspired adhesives, to resist biofouling, and to play a role in the “feel” of an object during tactile interaction. Here, we investigate the damage to micropillar arrays comprising pillars of different modulus, spacing, diameter, and aspect ratio due to the sliding of a silicone cast of a human finger. The goal is to determine the effect of these parameters on the types of damage observed, including adhesive failure and ploughing of material from the finger onto the array. Our experiments point to four principal conclusions [1]. Aspect ratio is the dominant parameter in determining survivability through its effect on the bending stiffness of micropillars [2]. All else equal, micropillars with larger diameter are less susceptible to breakage and collapse [3]. The spacing of pillars in the array largely determines which type of adhesive failure occurs in non-surviving arrays [4]. Elastic modulus plays an important role in survivability. Clear evidence of elastic recovery was seen in the more flexible polymer and this recovery led to more instances of pristine survivability where the stiffer polymer tended to ablate PDMS. We developed a simple model to describe the observed bending of micropillars, based on the quasi-static mechanics of beam-columns, that indicated they experience forces ranging from 10−4–10−7 N to deflect into adhesive contact. Taken together, results obtained using our framework should inform design considerations for microstructures intended to be handled by human users.

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Section: Resultsmentioning

confidence: 99%

Survival of polymeric microstructures subjected to interrogatory touch

et al. 2021

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“…This effect may be significant, especially for the actuators with 10 electrodes because they have a large volume. The third is a slight reduction in the actuator volume due to the extraction of uncross-liked material during the immersion in the solvent ( Glover et al, 2020 ). This may make the dielectric layers slightly thinner and, in turn, the actuation strokes larger due to an increase in the electrostatic stress.…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, by identifying and incorporating softer elastomers that are compatible with our method, the actuation strains of our actuators can be expected to become larger. Candidates for such elastomers include the Ecoflex series described above and Sylgard 184 with a modified mixing ratio ( Glover et al, 2020 ). It should be noted that this work will also require the exploration of suitable solvents and the investigation of their influence on the mechanical, material, and electrical properties of chosen elastomers.…”

Section: Discussionmentioning

confidence: 99%

Monolithic Stacked Dielectric Elastomer Actuators

et al. 2021

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Dielectric elastomer actuators (DEAs) are a promising actuator technology for soft robotics. As a configuration of this technology, stacked DEAs afford a muscle-like contraction that is useful to build soft robotic systems. In stacked DEAs, dielectric and electrode layers are alternately stacked. Thus, often a dedicated setup with complicated processes or sometimes laborious manual stacking of the layers is required to fabricate stacked actuators. In this study, we propose a method to monolithically fabricate stacked DEAs without alternately stacking the dielectric and electrode layers. In this method, the actuators are fabricated mainly through two steps: 1) molding of an elastomeric matrix containing free-form microfluidic channels and 2) injection of a liquid conductive material that acts as an electrode. The feasibility of our method is investigated via the fabrication and characterization of simple monolithic DEAs with multiple electrodes (2, 4, and 10). The fabricated actuators are characterized in terms of actuation stroke, output force, and frequency response. In the actuators, polydimethylsiloxane (PDMS) and eutectic gallium–indium (EGaIn) are used for the elastomeric matrix and electrode material, respectively. Microfluidic channels are realized by dissolving a three-dimensional printed part suspended in the elastomeric structure. The experimental results show the successful implementation of the proposed method and the good agreement between the measured data and theoretical predication, validating the feasibility of the proposed method.

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“…Young's moduli of commercial silicone elastomers are generally larger than 0.6 MPa [19]. Softer silicone elastomers have been realized through addition of solvents [20]- [23], sparse crosslinking [24]- [26] and crosslinking of bottle-brush polydimethylsiloxane (PDMS) [27], [28]. Synthesizing bottle-brush PDMS often requires complex procedures [29].…”

Section: Introductionmentioning

confidence: 99%

Super-stretchable silicone elastomer applied in low voltage actuators

Madsen

Skov

2021

Electroactive Polymer Actuators and Devices (EAPAD) XXIII

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Enabling desirable actuations at low voltages for silicone based dielectric elastomer actuators (DEAs) is challenging. Reducing the thickness and increasing the softness of the silicone film are key approaches for this purpose. In this work, a super-stretchable silicone elastomer was characterized and used as DEA. The prepared elastomer can be stretched uniaxially to 2400% strain, allowing a significant thickness reduction through pre-stretches. Besides, it shows a moderate average elastic modulus of 0.32 MPa even at strains of 1000%-1500%. These properties favor its application in DEAs. Actuation results show that the elastomer was not only actuated to a high strain but also actuated at attractive voltages. Specifically, a 1 mm-thick elastomer with a pre-strain of 200%×200% was actuated 45% in area at 4 kV, and a 0.25 mmthick elastomer film with pre-strain of 600%×600% showed a 3% actuation strain at only 120 V. Considering its easy fabrication and excellent actuation performance at low voltages, the elastomer is promising in the application in DEAs.

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Extracting uncrosslinked material from low modulus sylgard 184 and the effect on mechanical properties

Cited by 46 publications

References 60 publications

Survival of polymeric microstructures subjected to interrogatory touch

Survival of polymeric microstructures subjected to interrogatory touch

Monolithic Stacked Dielectric Elastomer Actuators

Super-stretchable silicone elastomer applied in low voltage actuators

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