scholarly journals Configuration of Multifunctional Polyimide/Graphene/Fe3O4 Hybrid Aerogel-Based Phase-Change Composite Films for Electromagnetic and Infrared Bi-Stealth

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3038
Author(s):  
Tao Shi ◽  
Zhiheng Zheng ◽  
Huan Liu ◽  
Dezhen Wu ◽  
Xiaodong Wang

Electromagnetic (EM) and infrared (IR) stealth play an important role in the development of military technology and the defense industry. This study focused on developing a new type of multifunctional composite film based on polyimide (PI)/graphene/Fe3O4 hybrid aerogel and polyethylene glycol (PEG) as a phase change material (PCM) for EM and IR bi-stealth applications. The composite films were successfully fabricated by constructing a series of PI-based hybrid aerogels containing different contents of graphene nanosheets and Fe3O4 nanoparticles through prepolymerizaton, film casting, freeze-drying, and thermal imidization, followed by loading molten PEG through vacuum impregnation. The construction of PI/graphene/Fe3O4 hybrid aerogel films provides a robust, flexible, and microwave-absorption-functionalized support material for PEG. The resultant multifunctional composite films not only exhibit high microwave absorption effectiveness across a broad frequency range, but also show a good ability to implement thermal management and temperature regulation under a high latent-heat capacity of over 158 J/g. Most of all, the multifunctional composite films present a wideband absorption capability at 7.0–16.5 GHz and a minimum reflection loss of −38.5 dB. This results in excellent EM and IR bi-stealth performance through the effective wideband microwave absorption of graphene/Fe3O4 component and the thermal buffer of PEG. This study offers a new strategy for the design and development of high-performance and lightweight EM–IR bi-stealth materials to meet the requirement of stealth and camouflage applications in military equipment and defense engineering.

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1243 ◽  
Author(s):  
Chunmei Zhang ◽  
Tianliang Zhai ◽  
Chao Zhan ◽  
Qiuping Fu ◽  
Chao Ma

The graphene nanosheets (GNS)/polydimethylsiloxane (PDMS) composite films with out-of-plane dielectric actuation behavior were prepared through a layer-by-layer spin coating process. The GNS-PDMS/PDMS composite films with 1~3 layers of GNS-PDMS films were spin coated on top of the PDMS film. The dielectric, mechanical, and electromechanical actuation properties of the composite films were investigated. The dielectric constant of the GNS-PDMS3/PDMS composite film at 1 kHz is 5.52, which is 1.7 times that of the GNS-PDMS1/PDMS composite film. The actuated displacement of the GNS-PDMS/PDMS composite films is greatly enhanced by increasing the number of GNS-PDMS layers. This study provides a novel alternative approach for fabricating high-performance actuators with out-of-plane actuation behavior.


2020 ◽  
Vol 391 ◽  
pp. 123512 ◽  
Author(s):  
Ying Li ◽  
Fanbin Meng ◽  
Yuan Mei ◽  
Huagao Wang ◽  
Yifan Guo ◽  
...  

RSC Advances ◽  
2016 ◽  
Vol 6 (51) ◽  
pp. 45595-45604 ◽  
Author(s):  
Mohammad Mehrali ◽  
Sara Tahan Latibari ◽  
Marc A. Rosen ◽  
Amir Reza Akhiani ◽  
Mohammad Sajad Naghavi ◽  
...  

A novel shape-stabilized phase change material (SSPCM) was fabricated by using a vacuum impregnation technique for solar-thermal energy storage applications.


Author(s):  
Peng Wang ◽  
Zhongbin Pan ◽  
Weilin Wang ◽  
Jianxu Hu ◽  
Jinjun Liu ◽  
...  

High-performance electrostatic capacitors are in urgent demand owing to the rapidly development of advanced power electronic applications. However, polymer-based composite films with both high breakdown strength (Eb) and dielectric constant...


Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1908
Author(s):  
Hai Li ◽  
Sooman Lim

Self-polarized piezoelectric devices have attracted significant interest owing to their fabrication processes with low energy consumption. Herein, novel poling-free piezoelectric nanogenerators (PENGs) based on self-polarized polyvinylidene difluoride (PVDF) induced by the incorporation of different surface-modified barium titanate nanoparticles (BTO NPs) were prepared via a fully printing process. To reveal the effect of intermolecular interactions between PVDF and NP surface groups, BTO NPs were modified with hydrophilic polydopamine (PDA) and hydrophobic 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES) to yield PDA-BTO and PFD-BTO, respectively. This study demonstrates that the stronger hydrogen bonding interactions existed in PFD-BTO/PVDF composite film comparative to the PDA-BTO/PVDF composite film induced the higher β-phase formation (90%), which was evidenced by the XRD, FTIR and DSC results, as well as led to a better dispersion of NPs and improved mechanical properties of composite films. Consequently, PFD-BTO/PVDF-based PENGs without electric poling exhibited a significantly improved output voltage of 5.9 V and power density of 102 μW cm−3, which was 1.8 and 2.9 times higher than that of PDA-BTO/PVDF-based PENGs, respectively. This study provides a promising approach for advancing the search for high-performance, self-polarized PENGs in next-generation electric and electronic industries.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jae-Won Lee ◽  
Joon Young Cho ◽  
Mi Jeong Kim ◽  
Jung Hoon Kim ◽  
Jong Hwan Park ◽  
...  

AbstractSoft electronic devices that are bendable and stretchable require stretchable electric or electronic components. Nanostructured conducting materials or soft conducting polymers are one of the most promising fillers to achieve high performance and durability. Here, we report silver nanoparticles (AgNPs) embedded with single-walled carbon nanotubes (SWCNTs) synthesized in aqueous solutions at room temperature, using NaBH4 as a reducing agent in the presence of highly oxidized SWCNTs as efficient nucleation agents. Elastic composite films composed of the AgNPs-embedded SWCNTs, Ag flake, and polydimethylsiloxane are irradiated with radiation from a Xenon flash lamp within a time interval of one second for efficient sintering of conductive fillers. Under high irradiation energy, the stretchable electrodes are created with a maximum conductivity of 4,907 S cm−1 and a highly stretchable stability of over 10,000 cycles under a 20% strain. Moreover, under a low irradiation energy, strain sensors with a gauge factor of 76 under a 20% strain and 5.4 under a 5% strain are fabricated. For practical demonstration, the fabricated stretchable electrode and strain sensor are attached to a human finger for detecting the motions of the finger.


2021 ◽  
Author(s):  
Liwei Zhu ◽  
Ning Liu ◽  
Xincheng Lv ◽  
Ziqiu Zhang ◽  
Liangmin Yu ◽  
...  

A novel carbon nanomaterial with unique morphology was prepared and proven to be an effective material for EMWA and electrochemical energy storage.


Nanoscale ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 3079-3091
Author(s):  
Libo Chang ◽  
Zhiyuan Peng ◽  
Tong Zhang ◽  
Chuying Yu ◽  
Wenbin Zhong

Wood-inspired HCNF@Lig introduced into MXenes constructing a nacre-like material with high mechanical strength and excellent flexibility used as a flexible supercapacitor.


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