Modular reprogrammable 3D mechanical metamaterials with unusual hygroscopic deformation modes

Yisong, Bai; Liu, Chuanbao; Li, Yang; Li, Jinxu; Qiao, Lijie; Zhou, Ji; Bai, Yang

doi:10.1039/d3mh00694h

Cited by 2 publications

(3 citation statements)

References 57 publications

(73 reference statements)

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“…39,40 The absorption of moisture by the resin leads to swelling, wherein various components within the packaging materials exhibit different swelling tendencies, and this divergence generates hygroscopic stress, impacting the material's longevity. 41,42 Moreover, the presence of water molecules, being polar, can influence the dielectric properties of the material. 43 Figure 7c illustrates the variation in the water absorption by the resin.…”

Section: Coefficient Of Thermal Expansion (Cte)mentioning

confidence: 99%

Curing Behavior and Properties of Active Ester Cured Cycloaliphatic Epoxy Resins

Liu,

Qin,

Cui

et al. 2024

Ind. Eng. Chem. Res.

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Cycloaliphatic epoxy resins are known for their synthesis process that eliminates hydrolyzable chlorine, thus avoiding the hydrolysis of hydrolyzable chlorine to hydroxyl groups in conventional epoxies, which is very favorable for the preparation of low dielectric epoxy resins. The curing process using active ester generates no hydroxyl groups, also indicating a promising approach for producing low dielectric epoxy resins. However, the resistance of cycloaliphatic epoxy to nucleophilic reactions restricts it from reacting usually only with anhydrides. This study investigates the reactivity of the active ester with cycloaliphatic epoxy, demonstrating its capability to undergo complete curing reactions at temperatures near 150 °C. Factors influencing this process, including the volatilization of the catalyst DMAP and its reactivity, are examined. Two types of cycloaliphatic epoxies (3,4-epoxycyclohexylmethyl-3′,4'-epoxycyclohexane carboxylate (EEC) and bis (3,4-epoxycyclohexylmethyl) adipate (BEA)) are combined with an active ester hardener, triacetyl resveratrol (TAR), to prepare epoxy resins. The activation energies for the curing reactions are determined, and the optimal concentration of catalyst 4-dimethylaminopyridine (DMAP) is identified for each resin. The use of catalysts at specific concentrations results in resins with superior mechanical properties (91.7 and 71.4 MPa for EEC/TAR and BEA/TAR), excellent thermal stability (T d5% of 354 and 347 °C), and good dielectric properties (dielectric constant of 3.68 and 3.95 at 10 MHz), outperforming anhydride-cured cycloaliphatic epoxy resins. These findings expand the selection of hardeners for cycloaliphatic epoxy resins and highlight the potential of the prepared resins in electronic packaging materials, offering enhanced properties suitable for various applications.

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Section: Coefficient Of Thermal Expansion (Cte)mentioning

confidence: 99%

Curing Behavior and Properties of Active Ester Cured Cycloaliphatic Epoxy Resins

Liu,

Qin,

Cui

et al. 2024

Ind. Eng. Chem. Res.

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“…For example, an off-center distributed fiber was produced by a continuous fiber DIW device, and the actuator can be constructed directly in space to achieve programmatic deformation . Bai et al used fused deposition modeling to make 3D mechanical metamaterials with filaments, which capable of accomplishing homogeneous or complex deformations when stimulated by humidity . Xin et al reported a mechanical metamaterials actuator based on chiral metamaterials fibers with tunable, programmable, and reconfigurable properties .…”

Section: Structures Of Fiber/textile Actuatorsmentioning

confidence: 99%

“…60 modeling to make 3D mechanical metamaterials with filaments, which capable of accomplishing homogeneous or complex deformations when stimulated by humidity. 61…”

Section: Structures Of Fiber/textile Actuatorsmentioning

confidence: 99%

Soft Fiber/Textile Actuators: From Design Strategies to Diverse Applications

Xue,

Liu,

et al. 2023

ACS Nano

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Fiber/textile-based actuators have garnered considerable attention due to their distinctive attributes, encompassing higher degrees of freedom, intriguing deformations, and enhanced adaptability to complex structures. Recent studies highlight the development of advanced fibers and textiles, expanding the application scope of fiber/textile-based actuators across diverse emerging fields. Unlike sheet-like soft actuators, fibers/textiles with intricate structures exhibit versatile movements, such as contraction, coiling, bending, and folding, achieved through adjustable strain and stroke. In this review article, we provide a timely and comprehensive overview of fiber/textile actuators, including structures, fabrication methods, actuation principles, and applications. After discussing the hierarchical structure and deformation of the fiber/textile actuator, we discuss various spinning strategies, detailing the merits and drawbacks of each. Next, we present the actuation principles of fiber/fabric actuators, along with common external stimuli. In addition, we provide a summary of the emerging applications of fiber/textile actuators. Concluding with an assessment of existing challenges and future opportunities, this review aims to provide a valuable perspective on the enticing realm of fiber/textile-based actuators.

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Modular reprogrammable 3D mechanical metamaterials with unusual hygroscopic deformation modes

Abstract: The majority of polymer-based materials demonstrate expansion upon absorbing water from the air. Mechanical metamaterials provide an interesting way to achieve unusual hygroscopic deformation. However, previous works only accommodate the...

Cited by 2 publications

References 57 publications

Curing Behavior and Properties of Active Ester Cured Cycloaliphatic Epoxy Resins

Curing Behavior and Properties of Active Ester Cured Cycloaliphatic Epoxy Resins

Soft Fiber/Textile Actuators: From Design Strategies to Diverse Applications

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