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Understanding the depolarization of ferroelectric materials caused by external stimuli is critical for maintaining the aligned polarization states. Although thermal depolarization in poled materials is well established, the mechanisms of electric field-induced depolarization remain largely unexplored. In this study, we investigate the electrical depoling behavior of [001]-oriented rhombohedral Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) single crystals poled using direct current poling (DCP) and alternating current poling (ACP). We reveal that the ACP sample exhibits a lower reverse coercive field than the DCP specimen. We compare the effects of bipolar and unipolar electric fields applied in the reverse poling direction, analyzing the changes in permittivity and piezoelectric resonance. Piezoresponse force microscopy is employed to characterize domain configurations in poled and electrically depoled samples. Our findings suggest that property degradation may arise from the nucleation and growth of domains oriented opposite to the initial arrangement. 

Abstract Tailored ribbing structures are obtained by large‐scale rolling in polymer PDMS thin‐films by adding carbon nanotubes (CNT) inclusions, which significantly improved the mechanical behavior of systems subjected to dynamic compressive strain rates. A nonlinear explicit dynamic three‐dimensional finite‐element (FE) scheme is used to understand and predict the thermomechanical response of the manufactured ribbed thin‐film structures subjected to dynamic in‐plane compressive loading. Representative volume element (RVE) FE models of the ribbed thin‐films are subjected to strain rates as high as 10⁴s⁻¹in both the transverse and parallel ribbing directions. Latin Hypercube Sampling of the microstructural parameters, as informed from experimental observations, provide the microstructurally based RVEs. An interior‐point optimization routine is also employed on a regression model trained from the FE predictions that can be used to design ribbed materials for multifunctional applications. The model verifies that damage can be mitigated in CNT‐PDMS systems subjected to dynamic compressive loading conditions by controlling the ribbing microstructural characteristics, such as the film thickness and the ribbing amplitude and wavelength. This approach provides a framework for designing materials that can be utilized for applications that require high strain rate damage tolerance, drag reduction, antifouling, and superhydrophobicity. 

Solar panels contributed to over 115,000 GWh of energy being produced in the United States and solar panel energy consumption has increased by 27 % at the start of the 21st century. Given the decrease of photovoltaic efficiency at higher temperatures and the increasing demand for clean energy, the development of an economical technology for solar panel cooling is necessary. Passive cooling can be achieved by infrared radiating into space. Typical solar arrays require large functional areas in order to supply a significant amount of power as compared to other sources. As such, any method to help reduce the temperature of the solar panel surfaces needs to maintain manufacturing scalability for sustainable use. We demonstrate a rapid, low-cost, template-free roll coating method to fabricate photonic composite film with SiO2 nanoparticles which possess high emissivity in the atmospheric transparent window while passing visible and near infrared light to photovoltaics beneath. When facing direct sunlight at summer noon, the coatings show a 3.5°C temperature decrease without loss of photovoltaic efficiency while having hydrophobic and contamination-resistance merits.