Programming complex shapes in thin nematic elastomer and glass sheets

Plucinsky, Paul; Lemm, Marius; Bhattacharya, Kaushik

doi:10.1103/physreve.94.010701

Cited by 53 publications

(66 citation statements)

References 21 publications

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“…Anchoring shape-morphing LCE films is expected to be critical in allowing the integration of these materials into a range of proposed applications such as haptic displays [8], microfluidic pumps [25], or reconfigurable optical devices [26]. A few anchorable profiles have been proposed in [14]. However, these patterns rely on the exotic property ν > 1 (sometimes found in nematic glasses), whereas LCEs characteristically exhibit volumeconserving deformations corresponding to ν ∼ 0.5.…”

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confidence: 99%

Curvature by design and on demand in liquid crystal elastomers

et al. 2018

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The shape of liquid crystalline elastomers (LCEs) with spatial variation in the director orientation can be transformed by exposure to a stimulus. Here, informed by previously reported analytical treatments, we prepare complex spiral patterns imprinted into LCEs and quantify the resulting shape transformation. Quantification of the stimuli-induced shapes reveals good agreement between predicted and experimentally observed curvatures. We conclude this communication by reporting a design strategy to allow LCE films to be anchored at their external boundaries onto rigid substrates without incurring internal, mechanical-mismatch stresses upon actuation, a critical advance to the realization of shape transformation of LCEs in practical device applications.Liquid crystal elastomers (LCEs) are exciting materials that show promise for enabling multifunctional character in flexible devices. The mechanical response of these materials is inherently and programmably anisotropic, governed by the molecular-level liquid crystalline orientation. This generates a rich variety of reversible, shape-morphing behaviors [1] with large strains

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confidence: 99%

Curvature by design and on demand in liquid crystal elastomers

et al. 2018

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“…A circular “radial-azimuthal” domain aligned with the sample center, will induce out-of-plane folds in the cross sample also creating a box morphology. This results illustrate how FEM simulations can further study complex shape evolution of samples based on well-controlled nematic microstructures and engineer stimuli-responsive polymeric devices891617.…”

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confidence: 70%

Modeling out-of-plane actuation in thin-film nematic polymer networks: From chiral ribbons to auto-origami boxes via twist and topology

Gimenez-Pinto

Mbanga

et al. 2017

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Various experimental and theoretical studies demonstrate that complex stimulus-responsive out-of-plane distortions such as twist of different chirality, emergence of cones, simple and anticlastic bending can be engineered and pre-programmed in a liquid crystalline rubbery material given a well-controlled director microstructure. Via 3-d finite element simulation studies, we demonstrate director-encoded chiral shape actuation in thin-film nematic polymer networks under external stimulus. Furthermore, we design two complex director fields with twisted nematic domains and nematic disclinations that encode a pattern of folds for an auto-origami box. This actuator will be flat at a reference nematic state and form four well-controlled bend distortions as orientational order changes. Device fabrication is applicable via current experimental techniques. These results are in qualitative agreement with theoretical predictions, provide insight into experimental observations, and demonstrate the value of finite element methods at the continuum level for designing and engineering liquid crystal polymeric devices.

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“…The fundamental idea of shape morphing is to write a heterogeneous pattern of director field on a thin sheet that when actuated creates a pattern of spontaneous stretch that is not compatible in the plane, thereby leading the sheet to a complex three-dimensional shape. This can be described using a metric constraint [6,1,23] that relates the three-dimensional deformation y of the midplane of a thin sheet ω ⊂ R 2 to the induced metric due to the actuation (described by a parameter r ≡ r(∆T ) > 0 with r = 1 prior to actuation and ∈ (0, 1) for heating) and a director pattern n 0 : ω → S 2 :…”

Section: Metric Constraintmentioning

confidence: 99%

“…First, all the patterns described in the literature [18,16,4,29,19,1,21,22,23,24] have multiple, energetically degenerate actuated configurations. For example, the cone can actuate either up or down.…”

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confidence: 99%

Patterning nonisometric origami in nematic elastomer sheets

et al. 2018

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Nematic elastomers dramatically change their shape in response to diverse stimuli including light and heat. In this paper, we provide a systematic framework for the design of complex three dimensional shapes through the actuation of heterogeneously patterned nematic elastomer sheets. These sheets are composed of nonisometric origami building blocks which, when appropriately linked together, can actuate into a diverse array of three dimensional faceted shapes. We demonstrate both theoretically and experimentally that the nonisometric origami building blocks actuate in the predicted manner, and that the integration of multiple building blocks leads to complex, yet predictable and robust, shapes. We then show that this experimentally realized functionality enables a rich design landscape for actuation using nematic elastomers. We highlight this landscape through examples, which utilize large arrays of these building blocks to realize a desired three dimensional origami shape. In combination, these results amount to an engineering design principle, which provides a template for the programming of arbitrarily complex three dimensional shapes on demand.

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Programming complex shapes in thin nematic elastomer and glass sheets

Cited by 53 publications

References 21 publications

Curvature by design and on demand in liquid crystal elastomers

Curvature by design and on demand in liquid crystal elastomers

Modeling out-of-plane actuation in thin-film nematic polymer networks: From chiral ribbons to auto-origami boxes via twist and topology

Patterning nonisometric origami in nematic elastomer sheets

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