Unparalleled Dielectric‐Switching Effects Caused by Dual Polarization Synergy (Adv. Funct. Mater. 28/2023)

Abstract

In article number 2214544, Ming Jiang, Lijie Dong, and co-workers propose a synergistic dielectric switching mechanism. The crystallization/melting behavior of octadecane induces the aggregation/dispersion of conducting micelles, resulting in a significant simultaneous enhancement/weakening of interfacial polarization and electrode polarization-the structural transition results in an unparalleled dielectric switching effect.

Hydrogen Bond Reorganization‐Enabled Dielectric Pulsing Effects in Polar Polymers

“…Consequently, the dielectric constant of PVDF/PEG dramatically increases, driven by the significant enhancement of interfacial polarization. [18][19][20][21]27,28,[49][50][51][52][53][54][55][56][57] In the second step, from 30 to 60 °C, corresponding to the part where the dielectric constant plummets, the hydrogen bond between PVDF and PEG is broken, evident from the blue shift of C─F, i.e., the enhancement of bonding energy (Figure 2f). This weakening of the interaction between PVDF and PEG contributes to a reduction in interfacial polarization, causing the dielectric constant to return to a low state.…”

“…In the FTIR spectra of PVDF/PEG/ILs (Figure S28, Supporting Information), a two-step hydrogen bond reorganization process is also observed, but this phenomenon is not found in the pure PVDF fibrous film (Figure S29, Supporting Information). Although IL is contained in PVDF/PEG/ILs compared to PVDF/PEGs, the primary effect on the dielectric pulse strength is the increase in the number of charge carriers, which enhances the electrode polarization, [21,22] while the origin of the pulse remains unchanged. Considering the prevalence of hydrogen bonding in polar polymers, we observe a similar dielectric pulsing effect using other polar semicrystalline polymers in place of PVDF (Note S4, Figure S30, Supporting Information).…”

“…[5][6][7][8][9][10][11][12] Extensive research has been conducted on manipulating the dielectric response behavior in various dielectric materials using external stimuli. The results indicate that, under thermal stimulation, the dielectric constant of thermo-responsive dielectric materials that may meet the above application requirements can undergo bistable, [13][14][15][16][17][18][19][20][21][22] linear, [23] pulsed, [24][25][26][27][28] or other response forms. [29,30] This phenomenon is called thermo-responsive dielectric behavior.…”

“…However, most dielectric-responsive materials cannot be prepared through a continuous and efficient process, and most do not have good mechanical or even self-supporting properties, which limits the potential engineering applications of many thermoresponsive dielectric materials. [14][15][16][17][18][19][20][21][22][24][25][26][27]29,30] In our recent study, [28] we prepared poly(ethylene glycol) (PEG)-poly(vinylidene fluoride) (PVDF) core-sheath nanofibers by solution blow spinning (SBS) method, which provided a solution for the continuous, efficient, and cost-effective preparation of thermo-responsive dielectric materials with good mechanical properties. In the above study, the activation energy of PVDF molecular chain motion was reduced through PEG plasticization, which induced 𝛼 c relaxation at crystal edge defects and promoted interfacial polarization and dipolar polarization, successfully triggering the room temperature dielectric pulsing effect.…”

Mechanical Stretch α‐Cyclodextrin Pseudopolyrotaxane Elastomer with Reversible Phosphorescence Behavior

“…[ 17 ] These phosphorescence systems have been successfully applied in the fields of cell imaging, [ 18 ] anti‐counterfeiting, [ 19 ] intelligent sensing, [ 20 ] and lighting devices. [ 21 ] However, expanding mechanical force‐responsive luminescence to the field of organic phosphorescence still faces some challenges. Mechanical deformation disrupts the interaction between chromophores and polymer matrix, aggravating chromophores vibration and oxygen microenvironment‐mediated non‐radiative quenching of the triplet states, leading to irreversible phosphorescence reduction or quenching in the deformation region.…”