Mechanical rolling of nickel nanowire-PVDF composites yields enhanced conductivity and electromagnetic shielding properties

Highly flexible and lightweight PVDF-based nickel nanowires (NiNWs) composites are promising candidates for electronic devices, particularly in electromagnetic shielding. However, the alignment of NiNWs within the PVDF matrix to achieve high electrical conductivity presents a significant challenge....

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Main Authors: Meghana Jois H S, Amanuel Gebrekrstos, Anastasia Elias
Format: Article
Language:English
Published: Elsevier 2025-09-01
Series:Results in Engineering
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Online Access:http://www.sciencedirect.com/science/article/pii/S2590123025027665
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author Meghana Jois H S
Amanuel Gebrekrstos
Anastasia Elias
author_facet Meghana Jois H S
Amanuel Gebrekrstos
Anastasia Elias
author_sort Meghana Jois H S
collection DOAJ
description Highly flexible and lightweight PVDF-based nickel nanowires (NiNWs) composites are promising candidates for electronic devices, particularly in electromagnetic shielding. However, the alignment of NiNWs within the PVDF matrix to achieve high electrical conductivity presents a significant challenge. In this study, we present a straightforward and scalable method to prepare aligned NiNWs-PVDF composites using mechanical shear force (i.e., rolling). We firstly synthesized conductive, high aspect ratio NiNWs; we then prepared thin films of PVDF/NiNWs composites with various NiNWs concentrations (40–70 wt.%) via solution casting. These solution-cast PVDF/NiNWs composites were then mechanically rolled, and alignment of the NiNWs and PVDF lamellae was achieved, as confirmed by TEM and SAXS images. The oriented NiNWs in the PVDF matrix exhibited superior electrical conductivity compared to solution-cast samples without mechanical rolling. Notably, the percolation threshold of the rolled films was lower than that of the samples that were not rolled. Furthermore, the rolling process increased both the β-phase formation and the overall crystallinity of the PVDF matrix, as evidenced by FTIR and DSC analyses, respectively. Owing to enhancement of conductivity and dielectric permittivity, rolled composites displayed a total shielding efficiency of -42 dB over the 12 – 18 GHz frequency band (relevant to satellite and microwave communications), compared with -32 dB for non-rolled (solution cast) samples. This performance can be attributed to an absorption-dominant shielding mechanism due to the enhancement of interfacial polarization and β-phase formation. Mechanically rolled films are good candidates for use in EMI shielding applications requiring thin and lightweight materials.
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spelling doaj-art-e5e25e00bd994eb69a6c02e1624eac132025-08-22T04:57:23ZengElsevierResults in Engineering2590-12302025-09-012710669910.1016/j.rineng.2025.106699Mechanical rolling of nickel nanowire-PVDF composites yields enhanced conductivity and electromagnetic shielding propertiesMeghana Jois H S0Amanuel Gebrekrstos1Anastasia Elias2Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G 1H9 CanadaDepartment of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G 1H9 CanadaCorresponding author.; Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G 1H9 CanadaHighly flexible and lightweight PVDF-based nickel nanowires (NiNWs) composites are promising candidates for electronic devices, particularly in electromagnetic shielding. However, the alignment of NiNWs within the PVDF matrix to achieve high electrical conductivity presents a significant challenge. In this study, we present a straightforward and scalable method to prepare aligned NiNWs-PVDF composites using mechanical shear force (i.e., rolling). We firstly synthesized conductive, high aspect ratio NiNWs; we then prepared thin films of PVDF/NiNWs composites with various NiNWs concentrations (40–70 wt.%) via solution casting. These solution-cast PVDF/NiNWs composites were then mechanically rolled, and alignment of the NiNWs and PVDF lamellae was achieved, as confirmed by TEM and SAXS images. The oriented NiNWs in the PVDF matrix exhibited superior electrical conductivity compared to solution-cast samples without mechanical rolling. Notably, the percolation threshold of the rolled films was lower than that of the samples that were not rolled. Furthermore, the rolling process increased both the β-phase formation and the overall crystallinity of the PVDF matrix, as evidenced by FTIR and DSC analyses, respectively. Owing to enhancement of conductivity and dielectric permittivity, rolled composites displayed a total shielding efficiency of -42 dB over the 12 – 18 GHz frequency band (relevant to satellite and microwave communications), compared with -32 dB for non-rolled (solution cast) samples. This performance can be attributed to an absorption-dominant shielding mechanism due to the enhancement of interfacial polarization and β-phase formation. Mechanically rolled films are good candidates for use in EMI shielding applications requiring thin and lightweight materials.http://www.sciencedirect.com/science/article/pii/S2590123025027665PVDF/NiNWs compositesAlignmentMechanical rollingElectrical conductivityβ-phaseEMI shielding application
spellingShingle Meghana Jois H S
Amanuel Gebrekrstos
Anastasia Elias
Mechanical rolling of nickel nanowire-PVDF composites yields enhanced conductivity and electromagnetic shielding properties
Results in Engineering
PVDF/NiNWs composites
Alignment
Mechanical rolling
Electrical conductivity
β-phase
EMI shielding application
title Mechanical rolling of nickel nanowire-PVDF composites yields enhanced conductivity and electromagnetic shielding properties
title_full Mechanical rolling of nickel nanowire-PVDF composites yields enhanced conductivity and electromagnetic shielding properties
title_fullStr Mechanical rolling of nickel nanowire-PVDF composites yields enhanced conductivity and electromagnetic shielding properties
title_full_unstemmed Mechanical rolling of nickel nanowire-PVDF composites yields enhanced conductivity and electromagnetic shielding properties
title_short Mechanical rolling of nickel nanowire-PVDF composites yields enhanced conductivity and electromagnetic shielding properties
title_sort mechanical rolling of nickel nanowire pvdf composites yields enhanced conductivity and electromagnetic shielding properties
topic PVDF/NiNWs composites
Alignment
Mechanical rolling
Electrical conductivity
β-phase
EMI shielding application
url http://www.sciencedirect.com/science/article/pii/S2590123025027665
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AT amanuelgebrekrstos mechanicalrollingofnickelnanowirepvdfcompositesyieldsenhancedconductivityandelectromagneticshieldingproperties
AT anastasiaelias mechanicalrollingofnickelnanowirepvdfcompositesyieldsenhancedconductivityandelectromagneticshieldingproperties