What is it about?
This study explores the influence of biodegradable poly(lactic acid) (PLA) when blended with poly(vinylidene fluoride) (PVDF) and expanded graphite (ExGr) on the electrical, electromagnetic interference shielding effectiveness (EMI SE), and piezoelectric properties of the blend nanocomposites. Temperature-gradient-introduced compression molding of neat PVDF and PVDF–x wt % PLA (x = 10, 20, 40) films results in the generation of the β-phase of PVDF along with γ- and α-phases. The compression-molded neat PVDF film exhibits a higher β-phase content in comparison to the PVDF–PLA blend and blend nanocomposites. The electrical conductivity increases for blend nanocomposites with higher PLA loading due to enhanced dispersion of graphite nanosheets, as evidenced through the FESEM analysis of selected samples. The impedance and the real part of relative permittivity analyses of blend nanocomposites support enhanced dispersion of ExGr particles with an increase in the PLA content in the blend. In finger tapping mode, the maximum output voltage of 2 V (average voltage of 1.5 V) is obtained for PVDF–10 wt % PLA–9 wt % ExGr hybrid nanocomposites due to the higher electroactive phase content. The total EMI SE of 0.2 mm thick PVDF–40 wt % PLA–9 wt % ExGr blend nanocomposite film obtained is 34 dB at 10 GHz, which is dominated by the absorption process. The EMI SE obtained in this work is better than those of many PVDF-based foams and aerogels. Thus, the blend nanocomposites hold promise in microwave absorption and piezoelectric nanogenerator applications.
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Why is it important?
Materials that exhibit absorption-dominated EMI shielding at microwave frequencies with environmental benignity, offering sustainable solutions, are in great demand. In order to overcome the limitations posed by metallic EMI shields, conducting polymer nanocomposites have been developed as the polymer-based EMI shield will be flexible, easily processable, and cost-effective.
Perspectives
The higher electrical conductivity and magnetic permeability of polymer nanocomposites can enhance the EMI SE dominated by the absorption process. Hence, tuning the electrical conductivity of conducting polymer nanocomposite-based shields to achieve EMI SE > 20 dB with a minimum thickness is very important. Also, the filler loading must be minimized without compromising the EMI shielding effect of the conducting polymer nanocomposites.
Dr Pratheep K Annamalai
University of Queensland
Read the Original
This page is a summary of: Influence of Biodegradable Poly(lactic acid) in Poly(vinylidene fluoride)-Based Conducting Multifunctional Blend Nanocomposites on the Structure, Morphology, Electrical, Electromagnetic Interference Shielding, and Piezoelectric Properties, ACS Applied Polymer Materials, January 2025, American Chemical Society (ACS),
DOI: 10.1021/acsapm.4c02915.
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