Custom 3D Printable Silicones with Tunable Stiffness

Durban, Matthew M.; Lenhardt, Jeremy M.; Wu, Amanda S.; Small, Ward; Bryson, Taylor M.; Perez‐Perez, Lemuel; Nguyen, Du T.; Gammon, Stuart A.; Smay, James E.; Duoss, Eric B.; Lewicki, James P.; Wilson, Thomas S.

doi:10.1002/marc.201700563

Cited by 61 publications

(29 citation statements)

References 47 publications

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“…Since the PDMS‐based materials typically exhibit poor temperature stability beyond −50 °C due to a crystallization transition occurring at −75 °C, the sterically hindered diphenyl moieties were incorporated into PDMS chains to achieve better low temperature stability and 3D printability. [ 130 ] The extrudable PDMS‐based ink could also be achieved by blending uncured PDMS liquid precursor with PDMS microbeads, due to capillary attraction induced by the liquid precursor. [ 131 ] Dynamic oscillatory measurements reveals that inks containing certain fractions of PDMS liquid precursor behaved like pastes, which are flowable at high shear stress and possess high storage moduli and yield stresses that are desirable for DIW.…”

Section: Materials Designs For 3d Printabilitymentioning

confidence: 99%

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Extrusion 3D Printing of Polymeric Materials with Advanced Properties

et al. 2020

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3D printing is a rapidly growing technology that has an enormous potential to impact a wide range of industries such as engineering, art, education, medicine, and aerospace. The flexibility in design provided by this technique offers many opportunities for manufacturing sophisticated 3D devices. The most widely utilized method is an extrusion‐based solid‐freeform fabrication approach, which is an extremely attractive additive manufacturing technology in both academic and industrial research communities. This method is versatile, with the ability to print a range of dimensions, multimaterial, and multifunctional 3D structures. It is also a very affordable technique in prototyping. However, the lack of variety in printable polymers with advanced material properties becomes the main bottleneck in further development of this technology. Herein, a comprehensive review is provided, focusing on material design strategies to achieve or enhance the 3D printability of a range of polymers including thermoplastics, thermosets, hydrogels, and other polymers by extrusion techniques. Moreover, diverse advanced properties exhibited by such printed polymers, such as mechanical strength, conductance, self‐healing, as well as other integrated properties are highlighted. Lastly, the stimuli responsiveness of the 3D printed polymeric materials including shape morphing, degradability, and color changing is also discussed.

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Section: Materials Designs For 3d Printabilitymentioning

confidence: 99%

“…The use of dynamic bonds which undergo reversible breaking, exchange and reformation could be utilized to modify the printability of polymers as well as imparting various advanced functions. [ 41–58,62–67,59,68,60,69,70,72,61,73,71,82,86–88,74–81,83–85,89–133,244,258 , …”

Section: Summary and Perspectivementioning

confidence: 99%

Extrusion 3D Printing of Polymeric Materials with Advanced Properties

et al. 2020

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“…Cu-S, Cu-M, Cu-L, and SS inks were each mixed with increasing levels of metal filler as shown in Table II. The catalyzed silicone was based on a Shore 50A hardness matrix formulation previously reported by Durban et al [24]. A Flacktek mixing cup was charged with a catalyzed Shore 50A durometer polysiloxane dispersion (5.0 g).…”

Section: B Sample Preparationmentioning

confidence: 99%

Development of the Multi-Material Inspection for Closed-Loop Rapid Optimization (MICRO) Sensor for Extrusion-Based Additive Manufacturing of Metal-Polymer Composite Inks

et al. 2021

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Additive Manufacturing (AM), or 3D printing, is a powerful technology that is revolutionizing the way designers create products across many industries. AM technology is severely limited by the lack of effective methods for in situ characterization of multi-material properties and composition during printing. The ability to detect the composition of multi-material printed inks in real time is an emerging need for a wide range of manufacturing applications. In this study, dielectric properties of embedded metal microparticles in a dielectric matrix are measured and characterized as a function of particle size, shape, volume percentage and frequency. Unexpectedly, there was no observation of any percolation threshold. The impedance was found to decrease with the percentage of metal filler as expected. While particle shape seemed to have significant effect on the impedance, there was little to no correlation between particle size and impedance. The resulting data can be used to generate a calibration curve correlating metal loading with impedance or capacitance. We discuss how this data can be used for in situ sensing of local ink composition, which does not currently exist, to facilitate greater control over the resulting properties and functionality of printed materials. Index Terms-3D printing, additive manufacturing, in situ monitoring, material sensor, metal-polymer composites. I. INTRODUCTION M ETAL-POLYMER composites have been widely studied for their unique combination of electrical and mechanical properties which lead to applications across a broad set of technologies. These applications include Manuscript

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“…Additive manufacturing has enabled the fabrication of new functional materials and structures with unique properties such as mechanical metamaterials, shape‐morphing structures, soft robotics, polymer‐derived ceramics, transparent glass, and biomaterials . However, multimaterial printing demonstrations have largely been limited to structures with binary switching between materials using multiple nozzles, or use nozzles designed for binary switches, leading to abrupt transitions in material properties between regions .…”

Section: Definition Of Circuit Model Variables and Fluidic Analogsmentioning

confidence: 99%

3D Printing of Compositional Gradients Using the Microfluidic Circuit Analogy

Nguyen

Yee

Dudukovic

et al. 2019

Adv Materials Technologies

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multimaterial DIW printer uses two separate ink dispensers joined at a single nozzle junction to simultaneously 3D print two viscoelastic inks through a single nozzle. Some models have been established to help control the printing of viscoelastic inks, but they have not been applicable for use in structures with complex compositional gradients. [18,22,23] As illustrated in Figure 1A, the toolpath of the printer is directly coupled with a desired composition (Φ) in order to determine the dispensing rate of each material. A distinction between the programmed dispensing rate of an ink (Q i ) and the measured flow rate out of the nozzle (Q Ni ) must be made when considering how to obtain an accurate compositional profile. Ideally, the increases and decreases in the measured ink flow rate synchronously follow the programmed dispensing rate. In reality, a number of factors introduce significant differences between the ideal ink dispensing rates and the realized outputs. Achieving accurate compositional 3D printing involving gradient transitions requires that we account for more complex behaviors, such as hydraulic compliance and non-Newtonian ink response, that result in significant differences between the programmed Q i and the realized Q Ni ( Figure 1B). For binary compositional changes within the same component, a combination of ink retraction and over extrusion can be used to account for these nonidealities. [22] For gradient compositional changes, the microfluidic circuit analogy (MCA) can be used to model and inform the ink dispensing profile that is required to achieve accurate compositional control ( Figure 1C).Here, we first describe the MCA model that is used to prescribe the ink-dispensing profile for improved compositional deposition accuracy in 3D-printed geometries with compositional gradients. We outline a calibration procedure to extract the MCA model parameters, which are then used in the MCA model to quantitatively guide the ink-dispensing profile for the desired compositional gradients to be printed. We finally validate the model in a DIW system using viscoelastic polydimethylsiloxane (PDMS) inks with time-dependent compositional changes. The ability to print multiple materials with accurate compositional profiles in a programmable manner enables the fabrication of new functional materials that were previously inaccessible.We use a model based on the microfluidic circuit analogy to determine the correct ink dispensing profiles required for 3D printing of structures with compositional gradients requires accurate dispensing control to achieve desired profiles. Here, empirical data are used with a model based on the microfluidic circuit analogy (MCA) to project dispense rate profiles that yield improved compositional accuracy in the printed part. Since minor variation in the experimental setup for each printing session can result in significant changes, a calibration procedure is developed to measure the system response. This calibration enables the extraction of the empirical MCA model parameters speci...

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Custom 3D Printable Silicones with Tunable Stiffness

Cited by 61 publications

References 47 publications

Extrusion 3D Printing of Polymeric Materials with Advanced Properties

Extrusion 3D Printing of Polymeric Materials with Advanced Properties

Development of the Multi-Material Inspection for Closed-Loop Rapid Optimization (MICRO) Sensor for Extrusion-Based Additive Manufacturing of Metal-Polymer Composite Inks

3D Printing of Compositional Gradients Using the Microfluidic Circuit Analogy

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