A combined compression and indentation study of mechanical metamaterials based on inverse opal coatings

Rosário, Jefferson J. do; Häntsch, Yen; Schneider, Gerold A.; Lilleodden, Erica T.

doi:10.1016/j.actamat.2020.04.025

Cited by 9 publications

(7 citation statements)

References 20 publications

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“…as-printed polymeric samples, the flat-punch indentation moduli from disk samples (Fig. 2a) are overlapping with previously reported moduli from micropillar compression tests 30 , which indicates that flat-punch indentation is as effective as pillar compression in extracting the mechanical properties 42 . The modulus-density scaling relationship, E ∝ ρ n shows an exponent n of ~2, consistent with the bending-dominated deformation mode 43 of log-pile structures and previously reported data 44 .…”

supporting

confidence: 87%

Ultra-low-density digitally architected carbon with a strutted tube-in-tube structure

Liu

Oakdale

et al. 2021

Nat. Mater.

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Porous materials with engineered stretching-dominated lattice designs, which offer attractive mechanical properties with ultra-light weight and large surface area for wide-ranging applications, have recently achieved near-ideal linear scaling between stiffness and density. Here, rather than optimizing the microlattice topology, we explore a different approach to strengthen low-density structural materials by designing tube-in-tube beam structures. We develop a process to transform fully dense, three-dimensional printed polymeric beams into graphitic carbon hollow tube-in-tube sandwich morphologies, where, similar to grass stems, the inner and outer tubes are connected through a network of struts. Compression tests and computational modelling show that this change in beam morphology dramatically slows down the decrease in stiffness with decreasing density. In situ pillar compression experiments further demonstrate large deformation recovery after 30-50% compression and high specific damping merit index. Our strutted tube-in-tube design opens up the space and realizes highly desirable high modulus-low density and high modulus-high damping material structures.

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supporting

confidence: 87%

Ultra-low-density digitally architected carbon with a strutted tube-in-tube structure

Liu

Oakdale

et al. 2021

Nat. Mater.

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“…Such misalignment can lead to imprecise measurements from buckling or inhomogeneous surface loading and maybe more pronounced in multilayered structures with layer thickness in sub-tens of microns . In contrast, methods such as nanoindentation and atomic force microscopy (AFM) are more suitable for assessing the surface properties of multilayered 3D printed structures, ,, particularly when the alignment between the applied force and layer orientation is critical. − …”

Section: Introductionmentioning

confidence: 99%

Nanoindentation Response of 3D Printed PEGDA Hydrogels in a Hydrated Environment

Khalili

Williams

Micallef

et al. 2023

ACS Appl. Polym. Mater.

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Hydrogels are commonly used materials in tissue engineering and organ-on-chip devices. This study investigated the nanomechanical properties of monolithic and multilayered poly(ethylene glycol) diacrylate (PEGDA) hydrogels manufactured using bulk polymerization and layer-by-layer projection lithography processes, respectively. An increase in the number of layers (or reduction in layer thickness) from 1 to 8 and further to 60 results in a reduction in the elastic modulus from 5.53 to 1.69 and further to 0.67 MPa, respectively. It was found that a decrease in the number of layers induces a lower creep index (CIT) in three-dimensional (3D) printed PEGDA hydrogels. This reduction is attributed to mesoscale imperfections that appear as pockets of voids at the interfaces of the multilayered hydrogels attributed to localized regions of unreacted prepolymers, resulting in variations in defect density in the samples examined. An increase in the degree of cross-linking introduced by a higher dosage of ultraviolet (UV) exposure leads to a higher elastic modulus. This implies that the elastic modulus and creep behavior of hydrogels are governed and influenced by the degree of cross-linking and defect density of the layers and interfaces. These findings can guide an optimal manufacturing pathway to obtain the desirable nanomechanical properties in 3D printed PEGDA hydrogels, critical for the performance of living cells and tissues, which can be engineered through control of the fabrication parameters.

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“…This tendency was in accordance with the compression test before a critical concentration of 1 × GNCs/MN (Figure b). However, the values of Young’s moduli obtained from the AFM indentation method (Figure S4) were different from the compression test (Table ), due to the different sizes and shapes of the samples and more specifically due to the different mechanisms of two testing methods …”

Section: Resultsmentioning

confidence: 91%

Glucose-Responsive Gold Nanocluster-Loaded Microneedle Patch for Type 1 Diabetes Therapy

Zhang

et al. 2020

ACS Appl. Bio Mater.

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Responsive blood glucose control in a convenient and noninvasive manner is the ultimate goal in diabetes treatment. In this study, we developed a closed-loop microneedle (MN)-array patch for transdermal and responsive insulin delivery in type 1 diabetes therapy. We prepared alginate-based MN-array patches integrated with glucose-responsive gold nanoclusters (GNCs) using a two-step casting and centrifuging process. From both theoretical calculation and experimental study, we found that the integration of GNCs into MNs significantly improved the mechanical strength of alginate-based MN-array patches. The GNCs facilitated the MNs to penetrate the skin of mice, and the glucose-responsive GNCs in MNs allowed the closed-loop insulin release both in vitro in glucose solutions and in vivo in type 1 diabetic mice. With transdermal application only once on the skin of mice, the MN-array patches regulated the blood glucose levels of mice in normoglycemic ranges for up to 2.8 days and decreased the diabetic symptoms of the mice. Our study proved the successful application of glucose-responsive GNC-loaded MN-array patches for minimally invasive and responsive insulin delivery, providing a promising alternative for type 1 diabetes therapy.

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A combined compression and indentation study of mechanical metamaterials based on inverse opal coatings

Cited by 9 publications

References 20 publications

Ultra-low-density digitally architected carbon with a strutted tube-in-tube structure

Ultra-low-density digitally architected carbon with a strutted tube-in-tube structure

Nanoindentation Response of 3D Printed PEGDA Hydrogels in a Hydrated Environment

Glucose-Responsive Gold Nanocluster-Loaded Microneedle Patch for Type 1 Diabetes Therapy

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