Dielectric relaxations of nanocomposites composed of HEUR polymers and magnetite nanoparticles

Campanella, Antonella; Brás, Ana R.; Raftopoulos, Konstantinos N.; Papadakis, C. M.; Vassiliadou, Olga; Kyritsis, Apostolos; Appavou, Marie-Sousai; Müller‐Buschbaum, Peter; Frielinghaus, Henrich

doi:10.1016/j.polymer.2016.04.045

Cited by 4 publications

(5 citation statements)

References 39 publications

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“…The fitted values of and with respect to irradiation time are shown in Fig. 4 f. The signal at the low frequency is relevant for the conductivity of the composite, which is directly correlated to the growth of Ag NPs, whereas the signal at the high frequency is associated with the segmental relaxation behaviors of DNA-CTMA [ 44 , 45 ], which is affected by the presence of surrounding Ag NP and Ag ions [ 46 , 47 ]. As the irradiation time increases, the concentration of Ag ions gradually decreases as they are used up for the formation of Ag NPs.…”

Section: Resultsmentioning

confidence: 99%

Kinetics and Mechanism of In Situ Metallization of Bulk DNA Films

et al. 2022

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DNA-templated metallization is broadly investigated in the fabrication of metallic structures by virtue of the unique DNA-metal ion interaction. However, current DNA-templated synthesis is primarily carried out based on pure DNA in an aqueous solution. In this study, we present in situ synthesis of metallic structures in a natural DNA complex bulk film by UV light irradiation, where the growth of silver particles is resolved by in situ time-resolved small-angle X-ray scattering and dielectric spectroscopy. Our studies provide physical insights into the kinetics and mechanisms of natural DNA metallization, in correlation with the multi-stage switching operations in the bulk phase, paving the way towards the development of versatile biomaterial composites with tunable physical properties for optical storage, plasmonics, and catalytic applications.

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Section: Resultsmentioning

confidence: 99%

Kinetics and Mechanism of In Situ Metallization of Bulk DNA Films

et al. 2022

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“…Nevertheless, α relaxation time in the function of temperature variations deviated from linearity and could be evaluated in terms of the Vogel–Fulcher–Tammann–Hesse (VFTH) equation [ 42, 50–52 ] :

τ ((), T) = τ_{0} e^{\frac{{DT}_{0}}{((), T - T_{0})}}

where τ 0 is a pre‐exponential factor, T 0 is the temperature of Vogel for the ideal temperature of glass transition T g . Normally, T 0 is 30–70 K under the temperature of glass transition T g .…”

Section: Resultsmentioning

confidence: 99%

“…where τ 0 a pre-exponential factor, E a the activation energy, and K B is the Boltzmann constant. Nevertheless, α relaxation time in the function of temperature variations deviated from linearity and could be evaluated in terms of the Vogel-Fulcher-Tammann-Hesse (VFTH) equation [42,[50][51][52] :…”

Section: Nanocompositesmentioning

confidence: 99%

Impact of cellulose nanocrystals reinforcement on molecular dynamics and dielectric properties of PCL‐based polyurethane

et al. 2021

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The thermal and dielectric properties of polymer nanocomposites based on polycaprolactone diol‐based PU matrix filled with various weight fractions of cellulose nanocrystals (CNCs) (from 0 to 10 wt%) extracted from the rachis of date palm tree were investigated by differential scanning calorimetry (DSC) and broadband dielectric spectroscopy. The emphasis was on clarifying the impact of the addition of CNC nanofillers on the molecular mobility of the PU matrix. Different dielectric relaxations have been found and the corresponding activation energies have been calculated, by means of the Havriliak–Negami model after fitting the dielectric data. The outcomes were explored in terms of molecular dynamics and interfacial processes. With 2.5 wt% of CNC, the strongest adhesion between matrix and reinforcement was acquired. This research was supported by the use of DSC for thermal properties.

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“…Thus, morphology dependent dynamic processes taking place in polymers, which are on multiple length scales and different time scales can be identi-ed in an effort to understand the structural states of these materials. [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] To date, various polymeric materials have been, and continues to be, analyzed by DRS. [13][14][15][16][17][18][19][20] In polyurethanes, this technique is mainly used to investigate the local dynamics, dynamic glass transition and indirectly, crystallinity and microphase morphology.…”

Section: Introductionmentioning

confidence: 99%

“…[13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] To date, various polymeric materials have been, and continues to be, analyzed by DRS. [13][14][15][16][17][18][19][20] In polyurethanes, this technique is mainly used to investigate the local dynamics, dynamic glass transition and indirectly, crystallinity and microphase morphology. [21][22][23][24][25][26][27][28] Combination of DSC and DRS enables us to gain a complete understanding of the structural variables, such as so segment type and molecular weight and hard segment structure and content on the molecular mobility and segmental dynamics in polyurethanes.…”

Section: Introductionmentioning

confidence: 99%