Ferroelectric nanodot formation from spin‐coated poly(vinylidene fluoride‐co‐trifluoroethylene) films and their application to organic solar cells

We demonstrated a facile route to the preparation of self‐assembled poly(vinylidene fluoride‐co‐trifluoroethylene) [P(VDF‐TrFE)] nanodots from spin‐coated thin films. We found that the initial film thickness would play an important role in the formation of such P(VDF‐TrFE) nanodots. Interestingly, the electric dipoles of such nanodots were self‐aligned toward the bottom electrode and their ferroelectric properties were determined by using piezoresponse force microscopy. In addition, the self‐polarized ferroelectric nanostructures were introduced to small molecular organic photovoltaic devices and allowed for enhancing the short circuit current density (J_sc) from 9.4 mA/cm² to 10.2 mA/cm² and the power conversion efficiency from 2.37% to 2.65%. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41230.     

Facile preparation of ferroelectric poly(vinylidene fluoride‐co‐trifluoroethylene) thick films by solution casting

We investigated the effects of annealing temperature and vacuum treatment on the crystallinity and ferroelectric properties of solution‐casted poly(vinylidenefluoride‐co‐trifluoroethylene), P(VDF‐TrFE), thick films. We varied the annealing temperature from 70°C to 150°C and achieved high‐quality ferroelectric thick films annealed at 130°C. Ferroelectric domains and their properties were confirmed using X‐ray diffraction, Fourier transform infrared spectroscopy with attenuated total reflection mode and ferroelectric/piezoelectric measurement systems. Drying and/or annealing in the vacuum allowed for the improvement of crystallinity and ferroelectric/piezoelectric properties. Importantly, the piezoelectric coefficient, d₃₃, of our optimal P(VDF‐TrFE) films after sufficient poling treatment was 36 pC/N and our P(VDF‐TrFE) power generator produced an output voltage of ～6 V under periodic bending and unbending motions. POLYM. ENG. SCI., 54:466–471, 2014. © 2013 Society of Plastics Engineers     

Effect of water absorption on the mechanical properties of poly(vinylidene fluoride‐trifluoroethylene) copolymer films

Electroactive polymers are smart materials that respond to electrical stimulation by changing their shape and size. The objective of this study is to investigate the applicability of the poly(vinylidene fluoride‐trifluoroethylene) (P(VDF‐TrFE)) copolymer in sensors or actuators in an in vivo environment. The basic mechanical properties of P(VDF‐TrFE) thin films were estimated by carrying out tensile and creep tests using specimens submerged in water at 30°C for a few weeks. Furthermore, X‐ray diffraction analysis was employed to observe the micro‐structural changes in the P(VDF‐TrFE) films due to water absorption wherein water intercalated in the interstitial sites between the chains of the P(VDF‐TrFE) films. Consequently, the mechanical properties of the P(VDF‐TrFE) films were enhanced due to water absorption. POLYM. ENG. SCI., 54:2654–2659, 2014. © 2013 Society of Plastics Engineers     

High polarization levels in poly(vinylidene fluoride–trifluoroethylene) ferroelectric thin films doped with diethyl phthalate

With a spin‐coating technique, ferroelectric thin films of poly(vinylidene fluoride–trifluoroethylene) copolymer [P(VDF–TrFE; with a content (mol %) ratio of 68/32 vinylidene fluoride/trifluoroethylene] were fabricated on silicon wafers covered with platinum and were doped with a nucleation agent, diethyl phthalate (DEP). The remnant polarization of copolymer thin films increased 70% after doping with DEP, and the coercive field was reduced, which is highly desirable in bistable memory devices. The dielectric constant of thin films also increased after doping. However, the effect of doping on the ferroelectric response was not remarkable in freestanding copolymer films. The results demonstrated that the ferroelectric dipole orientation in P(VDF–TrFE) thin films was significantly enhanced by the presence of DEP because the crystallinity of thin films decreased after doping, as revealed by X‐ray results. The dopant DEP acted as both a nucleation agent during the crystallization process and a plasticizer in the noncrystalline regions, which greatly enhanced the dipole orientation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1416–1419, 2003     

Dielectric properties and ferroelectric behavior of poly(vinylidene fluoride‐trifluoroethylene) 50/50 copolymer ultrathin films

Ultrathin films of poly(vinylidene fluoride‐trifluoroethylene) copolymer [P(VDF‐TrFE), with a content (mol %) ratio of 50/50 VDF/TrFE] were fabricated on silicon wafers covered with platinum by a spin‐coating technique, ranging in thickness from 20 nm to 1 μm. The effect of thickness on dielectric properties and polarization behavior was investigated. A critical thickness was found to be about 0.1 μm. An abrupt drop of dielectric constant was observed, although there is no significant change in dielectric loss at this thickness. Square and symmetric hysteresis loops were obtained in films thicker than 0.1 μm. However, for films thinner than 0.1 μm, fewer square hysteresis loops were observed. SEM and X‐ray results demonstrate that the effect of thickness on dielectric and ferroelectric properties could be explained by the changes of crystal structure in these films. In addition, the effects of irradiation on dielectric property and polarization response for ultrathin P(VDF‐TrFE) films were also presented. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2259–2266, 2001     

Electrical energy discharging performance of poly(vinylidene fluoride‐co‐trifluoroethylene) by tuning its ferroelectric relaxation with polymethyl methacrylate

Poly(methyl methacrylate) (PMMA) was introduced into ferroelectric Poly(vinylidene fluoride‐co‐trifluoroethylene) P(VDF‐co‐TrFE) via a simple solution blending process and a series of P(VDF‐co‐TrFE)/PMMA blends with varied PMMA content was obtained in an effort to investigate the confinement effect of PMMA on the crystalline, dielectric, and electric energy storage properties of P(VDF‐co‐TrFE). PMMA addition could reduce the crystallinity dramatically as well as the crystal size due to its dilution effect and impediment effect on the crystallization of P(VDF‐co‐TrFE). PMMA introduction is also responsible for the phase transition of P(VDF‐co‐TrFE) from α phase into γ phase. As expected, both the dielectric constant and loss of the blends are reduced as PMMA addition increases for the dilute, decoupling, and confinement effect of PMMA on the relaxation behavior of crystal phases of P(VDF‐co‐TrFE) under external electric field. As a result, both the maximum and remnant polarization of the blends are significantly depressed. The irreversible polarization of P(VDF‐co‐TrFE) is effectively restricted by the addition of PMMA due to its impeding effect on the crystallization of P(VDF‐co‐TrFE) and restricting effect on the switch of the polar crystal domains. Therefore, the energy loss induced by the ferroelectric relaxation of P(VDF‐co‐TrFE) is significantly reduced to less than 25% at an electric field of 450 MV/m while the energy storage density is well maintained at about 10 J/cm^?3 in the blend with 30 wt % PMMA. The results may help to understand how the ferroelectric relaxation affects the energy loss of ferroelectrics fundamentally and design more desirable materials for high energy storage capacitors. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40114.     

Evolution of morphology,ferroelectric, and mechanical properties in poly(vinylidene fluoride)–poly(vinylidene fluoride‐trifluoroethylene) blends

Considering the complementary properties of poly(vinylidene fluoride) (PVDF) and poly(vinylidene fluoride‐trifluoroethylene) [P(VDF‐TrFE)], it appears that their blends have the potential to be promising candidates for device applications. We report the evolution of morphology, ferroelectric, and mechanical properties (modulus and hardness) and their dependence on preparation temperature for PVDF–P(VDF‐TrFE) blends. From ferroelectric hysteresis measurements it was found that P(VDF‐TrFE) rich blends treated at higher temperature show significant values of remanent polarization. Remanent polarization values show a fourfold increase in these P(VDF‐TrFE) rich blends treated at higher temperature. Interestingly, blends prepared from high temperature showed greater value of remanent polarization even though they were found to consist of smaller amount of electroactive phase as compared to their low temperature treated counterpart. Nanoindentation experiments revealed that high temperature treatment improves the modulus of blends by at least 100%. This report attempts to tie these findings to the morphology and crystallinity of these blends. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45955.     

Effect of ultrasonication and other processing conditions on the morphology,thermomechanical, and piezoelectric properties of poly(vinylidene difluoride‐trifluoroethylene) copolymer films

This study is carried out on the effect of processing conditions including preparation methods, ultrasonication, film thickness, and thermal annealing on the thermal, mechanical, and piezoelectric properties of copolymer of poly(vinylidene difluoride‐trifluoroethylene) (P(VDF‐TrFE)). Free‐standing films and films on substrates are prepared by solvent casting and spin‐coating, respectively. The results obtained by differential scanning calorimetry show that the Curie transition of the copolymer films was influenced by the preparation methods, with very little difference in the melting transition. The difference was attributed to a less uniform distribution of TrFE comonomer units within the crystalline and amorphous regions of the spin‐coating films. However, no effect of the preparation methods on the piezoelectric properties of the films was observed. It is also found that the short ultrasonication, film thickness higher than critical value of crystallization of P(VDF‐TrFE) (about 100 nm), and drying before annealing did not have a significant effect on the properties of the films. Surprisingly, the ultrasonication had a clear impact on the relaxations at high temperature of the polymer chains. In addition, this study indicates that a short annealing by 10 min at 140°C was enough to obtain well‐crystallized films, which is interesting from the industrial point of view. POLYM. ENG. SCI., 54:1280–1288, 2014. © 2013 Society of Plastics Engineers     

All‐polymer electromechanical systems consisting of electrostrictive poly(vinylidene fluoride‐trifluoroethylene) and conductive polyaniline

The low elastic modulus and the ability to withstand high strain without failure make the conducting polymer attractive for a wide range of acoustic applications based on high‐strain electroactive polymers. In this article, we examine the electric and electromechanical performance of all‐polymer electromechanical systems, fabricated by painting conductive polyaniline (PANI) doped with camphor sulfonic acid (HCSA) on both sides of electrostrictive Poly(vinylidene fluoride‐trifluoroethylene) (P(VDF‐TrFE)) copolymer films, and compare them with those from the same copolymers with gold electrodes. The all‐polymer composite films are flexible, with strong coherent interfaces between the electrostrictive polymer layer and the conductive polymer layer. The electric performance such as dielectric properties and polarization hysteresis loops from P(VDF‐TrFE)/PANI film is nearly identical to those of P(VDF‐TrFE)/gold films in a wide temperature (from −50 to 120°C), and frequency range (from 1 Hz to 1 MHz). The all‐polymer systems also show a similar or even larger electric field induced strain response than that of films with electrodes under identical measurement conditions. The results demonstrate that the polyaniline/HCSA is good candidate material as the electrodes for electroactive polymers. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 945–951, 2000     

Tailoring the structural properties of PVDF and P(VDF‐TrFE) by using natural polymers as additives

The poly(vinylidene fluoride), PVDF, and its copolymer poly(vinylidene fluoride‐trifluoroethylene), P(VDF‐TrFE), are of great scientific and technological interest due to their ferro, pyro, and piezelectrical properties besides chemical and thermal stability. Recently, their biocompatibility has been shown as well. Therefore, considering all this potentiality, self‐standing films of PVDF and P(VDF‐TrFE) containing corn starch and latex of natural rubber as additives were produced by compressing/annealing forming blends. This process allows one to discard the necessity of using solvents to dissolve either PVDF or P(VDF‐TrFE), which are toxic to human. The films were structurally characterized through Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X‐ray diffraction, density, melt flow index, hardness, and thermal conductivity. The results showed that the polymers do not interact chemically with the additives leading to the formation of blends as physical mixtures where the additives are well dispersed within the blends at micrometer level. However, it was observed that the adhesion of the starch is better in the case of blends with P(VDF‐TrFE). Besides, the crystalline structures of the α‐PVDF and ferroelectric P(VDF‐TrFE) are kept in the blends. The density, hardness, melt flow index, and thermal conductivity values of the blends followed what should be expected from physical mixtures. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

Strengthening of electromechanical properties for poly(vinylidene fluoride‐trifluoroethylene) films under tailored electric cycling

Copolymers of polyvinylidene fluoride and trifluorethylene [P(VDF‐TrFE)] have potential applications in wearable and implantable electromechanical devices since they are mechanically flexible, and biocompatible. A tailored electric cyclic process is employed to enhance both electrical and mechanical properties in P(VDF‐TrFE) 65/35 mol % copolymer films. The films are subjected to lower and higher field magnitude electric cycling successively. For electrical properties, enhancement in remnant polarization, dielectric and piezoelectric constants occurs. From mechanical point of view, strengthening in the fracture strength happens. Wide‐angle X‐ray diffraction techniques examine changes of the orientation of the molecular chains, grain size, and crystallinity after electric cycling for the copolymer films. Scanning electron microscopy reveals evolutions of the microstructure, including rod‐like textures and fractography of the films. The results indicate that electric cycling causes the molecular chains to orient gradually along the direction perpendicular to the applied electric field. Consequently, an enhancement of 12.2% and 45% is realized for the remnant polarization and fracture strength, respectively for P(VDF‐TrFE) 65/35 copolymer film. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45926.     

Fabrication and properties of solution processed all polymer thin‐film ferroelectric device

A ferroelectric device, making use of a flexible plastic, polyethylenterephtalate (PET), as a substrate was fabricated by all solution processes. PET was globally coated by a conducting polymer, poly(3,4‐ethylenedioxythiophene) poly(styrenesulfonate) acid (PEDOT/PSSH), which is used as bottom electrode. The ferroelectric copolymer, poly(vinylidenefluoride–trifluoroethylene) (PVDF–TrFE), thin film was deposited by spin‐coating process from solution. The top electrode, polyaniline, was coated by solution process as well. The ferroelectric properties were measured on this all solution processed all polymer ferroelectric thin‐film devices. A square and symmetric hysteresis loop was observed with high‐polarization level at 15‐V drive voltage on a all polymer device with 700 Å (PVDF–TrFE) film. The relatively inexpensive conducting polyaniline electrode is functional well and therefore is a good candidate as electrode material for ferroelectric polymer thin‐film device. The remnant polarization P_r was 8.5 μC/cm² before the fatigue. The ferroelectric degradation starts after 1 × 10³ times of switching and decreases to 4.9 μC/cm² after 1 × 10⁵ times of switching. The pulse polarization test shows switching take places as fast as a few micro seconds to reach 90% of the saturated polarization. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Enhancement of dielectric and energy density properties in the PVDF‐based copolymer/terpolymer blends

We investigated the high dielectric constant and energy storage density for the blends of P(VDF‐TrFE) copolymer and P(VDF‐TrFE‐CFE) terpolymer. The degradation of coercive field (E_c) and remnant polarization (P_r) of the copolymer under an electric field of 125 MV/m was observed and the copolymer changed into a typical relaxor ferroelectric with doping of terpolymer. The dielectric constant of P(VDF‐TrFE) was found to be ～11, but was enhanced to ～55 by blending with P(VDF‐TrFE‐CFE) at 60 wt%. Consequently, a higher energy density of about 4.2 J/cm³ was obtained in these blends in contrast to about 3.6 J/cm³ in the terpolymer at the very low applied electric field of 125 MV/m. These results demonstrate the promise of blend approaches for tailoring and enhancing the dielectric properties of ferroelectric polymers. POLYM. ENG. SCI., 55:1396–1402, 2015. © 2015 Society of Plastics Engineers     

Solution‐derived ferroelectric vinylidene fluoride oligomer thin films with large polarization

Dense and uniform vinylidene fluoride (VDF) oligomer thin films with a highly polar β phase were prepared for the first time by a low‐cost and scalable solution casting approach, after treatments of substrate surface functionalization and hot‐pressing. Introducing hydrated salt in the precursor solution effectively promoted the ferroelectric β phase. The VDF oligomer thin films obtained with short molecular chains exhibited high crystallinity and high remnant polarization (91 mC m^?2), which is larger than both the polymer and copolymer counterpart films. The reasons for the observed low dielectric constant at low electric field, despite its larger polarization at high field, and the relatively high coercive field are discussed on the basis of the distinct structural characteristics of VDF oligomers. The low polar bulky end‐groups and difficulties in kink formation and propagation may result in the observed low dielectric constant at low electric field and the high coercive field. Copyright © 2011 Society of Chemical Industry     

Crystal phase of poly(vinylidene fluoride‐co‐trifluoroethylene) synthesized via hydrogenation of poly(vinylidene fluoride‐co‐chlorotrifluoroethylene)

Trifluoroethylene addition and thermal treatment induced crystal phase transition in a series of poly(vinylidene fluoride‐co‐trifluoroethylene) [P(VDF‐co‐TrFE)] containing varied TrFE molar ratio (6, 9, 12, and 20 mol %) prepared from the hydrogenation of poly(vinylidene fluoride‐co‐chlorotrifluoroethylene have been investigated by means of Fourier transform infrared spectral (FTIR), X‐ray diffraction (XRD), and differential scanning calorimetry (DSC) analyses. The comprehensive applications of the three techniques could distinguish α, β and γ phase of P(VDF‐co‐TrFE) very well. The multipeak fitting technique of DSC is successfully applied to calculate the percentage of different phases in the samples, which allows us to investigate the phase transition process of P(VDF‐co‐TrFE) precisely. It is found that the crystal phase of P(VDF‐co‐TrFE) films is turned from α + γ phase (6 mol % TrFE) to α + γ + β phase (9 and 12 mol % TrFE) to β phase (20 mol % TrFE) at high temperature, and from α + γ phase (6 mol % TrFE) to γ + β phase (9 mol % TrFE) to β phase (>12 mol % TrFE) at low fabricated temperature. Both the fabrication conditions and TrFE addition are responsible for the crystal phase transition of the hydrogenised P(VDF‐co‐TrFE). © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Influence of the processing parameters on the electrocaloric effect of poly(vinylidene fluoride–trifluoroethylene) copolymers

The influence of the processing parameters on the electrocaloric effect of a ferroelectric polymer was investigated. A normal ferroelectric poly(vinylidene fluoride–trifluoroethylene) [P(VDF–TrFE)] (55:45 mol %) copolymer was selected and fabricated. The crystallinity, microstructure, mechanical properties, and refrigeration capability of this copolymer were characterized with X‐ray diffraction, scanning electron microscopy, differential scanning calorimetry, and thermogravimetric analysis, respectively. We found that N,N‐dimethylformamide was the most suitable solvent for enhancing the crystallinity of the copolymer film. In combination with the consideration of the effect of the processing parameters on the microstructure of copolymer, a lower spin‐coating temperature and annealing temperature at 140 °C gave the highest crystallinity and uniform microstructure without defects. The highest temperature change was 12.13 °C when the copolymer film was operated at 110 °C under a higher electric field. The direct measurement of the refrigeration was carried out with an IR thermometer. We found that the P(VDF–TrFE) copolymer film had a considerable refrigeration capability, which increased as the applied electric field strength increased before electric breakdown. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44413.     

Synthesis and ferroelectric investigations of poly(vinylidene fluoride‐co‐hexafluoropropylene)‐Mg(NO3)2 films

The free‐standing, flexible, and ferroelectric films of poly(vinylidenefluoride‐co‐hexafluoropropylene) [P(VDF‐HFP)] were prepared by spin coating method. The ferroelectric phase of the films was enhanced by adding magnesium nitrate Mg(NO₃)₂ in different wt % as the additive during the film fabrication. The effects on the structural, compositional, morphological, ferroelectric, dielectric, and leakage current behaviors of the films due to the addition of salt were analyzed. Based on the X‐ray diffraction (XRD) patterns and Fourier Transform Infrared (FTIR) spectra, it is confirmed that the addition of Mg(NO₃)₂ promotes the electroactive β phase that induces the ferroelectric property. The fiber‐like topography of the films exhibits a nodule‐like structure, and the roughness of the films increases by the addition of Mg(NO₃)₂. The ferroelectric studies show the higher polarization values for the composite films than that of the plain P(VDF‐HFP) film. The Piezo‐response force microscope images also confirm the domain switching behavior of the samples. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44008.     

Tailored ferroelectric responses and enhanced energy density in PVDF‐based homopolymer/terpolymer blends

Blend of polymers is an effective way to tailor the ferroelectric responses and improve the energy storage properties of polymers. In this work, the microstructure and dielectric responses of the blends of poly(vinylidene fluoride) (PVDF) and poly(vinylidene fluoride‐trifluoroethylene‐chlorofluoroethylene) [P(VDF‐TrFE‐CFE)] have been studied. It is found that the addition of PVDF disturbs the crystallization process of P(VDF‐TrFE‐CFE), leading to lower crystallinity and smaller crystalline size. The aforementioned microstructure changes result in tailored ferroelectric responses. Dielectric responses show that the blend with 10 wt % PVDF achieves larger polarization response under high electric field (above 300 MV/m) due to the interfacial polarization. Because of the tailoring effect and the interfacial polarization, the blend with 10 wt % PVDF exhibits higher energy density and efficiency. Moreover, the breakdown strength (E_b) is also improved by adding a small amount of PVDF into the terpolymer. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40994.     

Low‐Cost,Damage‐Free Patterning of Lead Zirconate Titanate Films

The ability to pattern piezoelectric thin films without damage is crucial for the development of microelectromechanical systems. Direct patterning of complex oxides through microcontact printing was explored as an alternative to subtractive patterning. This process utilized an elastomeric stamp to transfer a chemical solution precursor of a piezoelectric material onto a substrate in a desired pattern. Polyurethane‐based stamps improved wetting of polar solutions on the stamp. This allowed for high‐fidelity patterning over multiple stamping cycles. Microcontact printing deposited patterned PbZr_0.52Ti_0.48O₃ layers from 0.1 to 1 μm in thickness. The lateral feature sizes attained varied from 5 to 500 μm. Upon crystallization at 700°C, the features formed phase‐pure perovskite PZT. The printed features had comparable electrical and electromechanical properties to those of continuous PZT films of similar thicknesses. For example, 1 μm thick PZT features had a permittivity of 1050 and a loss tangent of 0.02 at 10 kHz. The remanent polarization was 30 μC/cm², and the coercive field was 45 kV/cm. The piezoelectric coefficient e_31,f was ?7 C/m². These values indicated that the microcontact printing process did not adversely affect the PZT crystallization or properties for the thicknesses explored in this work.     

Mesophase Structure‐Enabled Electrostrictive Property in Nylon‐12‐Based Poly(ether‐block‐amide) Copolymers

To search for alternative electrostrictive polymers and to understand the underlying mechanism, the structure‐ferroelectric/electrostrictive property relationship for nylon‐12‐based poly(ether‐b‐amide) multiblock copolymers (PEBAX) is investigated. Two PEBAX samples are studied, namely, P6333 and P7033 with 37 and 25 mol.% of soft poly(tetramethylene oxide) (PTMO) blocks, respectively. In both samples, poorly hydrogen‐bonded mesophase facilitates electric field‐induced ferroelectric switching. Meanwhile, the longitudinal electrostrictive strain (S₁)–electric field (E) loops are obtained at 2 Hz. Different from conventional poly(vinylidene fluoride‐co‐trifluoroethylene) [P(VDF‐TrFE)]‐based terpolymers, uniaxially stretched nylon‐12‐based PEBAX samples exhibit negative S₁, that is, shrinking rather than elongation in the longitudinal direction. This is attributed to the unique conformation transformation of nylon‐12 crystals during ferroelectric switching. Namely, at a zero electric field, crystalline nylon‐12 chains adopt a more or less antiparallel arrangement of amide groups. Upon high‐field poling, ferroelectric domains are enforced with more twisted chains adopting a parallel arrangement of amide groups. Meanwhile, extensional S₁ is observed for P6333 at electric fields above 150 MV m^?1. This is attributed to the elongation of the amorphous phases (i.e., amorphous nylon‐12 and PTMO). Therefore, competition between shrinking S₁ from mesomorphic nylon‐12 crystals (i.e., nanoactuation) and elongational S₁ from amorphous phases determines the ultimate electrostriction behavior in stretched PEBAX films.