SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-026-4343-7
Piezoelectric materials interconvert mechanical and electrical energy, but piezoceramics are brittle while PVDF-based ferroelectric polymers exhibit low piezoelectric coefficients (d33 ≈ -30 pC N-1). Chemical modification via morphotropic phase boundary (MPB) engineering has raised d33 in P(VDF-TrFE) to -63.5 pC N-1, and to -69 pC N-1 with stretching, but intrinsic piezoelectricity in relaxor terpolymers remains limited. Here, relaxor ferroelectric P(VDF-TrFE-CFE) with varying C=C double bond (DB) content is synthesized via dehydrochlorination. Structural and electrical characterization reveals that increasing DB content stabilizes long-range ferroelectric order while suppressing short-range relaxor characteristics, forming a trans/helix phase boundary. At a critical DB content of 2.0 mol%, a markedly enhanced intrinsic d33 of -129.0 pC N-1 is achieved, outperforming previous MPB approaches. This finding addresses the fundamental bottleneck of low piezoelectric response in flexible ferroelectric polymers and provides a viable route for high-performance wearable electromechanical devices.
Chinese Journal of Environmental Engineering•2026•DOI: 10.12030/j.cjee.202508050
This study investigated the spatial distribution and ecological risk of heavy metals (As, Cd, Cr, Cu, Ni, Pb, Zn) in soil beneath an informal waste dump in a pastoral area of Baingoin County, Nagqu City, Tibet, a high-altitude cold region with frequent freeze-thaw cycles. A total of 55 soil samples were collected from surface (0 cm), middle (10-30 cm), and deep (50 cm) layers. Single-factor index (Pi), geo-accumulation index (Igeo), Nemerow index (PN), and risk assessment code (RAC) were employed to evaluate contamination levels and potential ecological risks, while Kriging interpolation was used to map spatial distribution. Results showed that average concentrations of all seven heavy metals exceeded local background values. Horizontally, high-concentration zones were mainly located at five points within the dump. Vertically, Cd, Cu, Pb, and Zn were significantly enriched in the surface layer, whereas Ni exhibited higher concentrations in deeper layers, indicating downward migration driven by freeze-thaw processes. All evaluation methods identified Cd as the primary pollutant. Speciation analysis revealed that heavy metals were predominantly in the residual fraction, with Ni having the highest weak-acid-extractable fraction (5.55%), indicating strong mobility and potential biological toxicity. This study fills a gap in systematic research on informal waste dumps in high-altitude ecologically fragile areas and provides a case reference for environmental management and remediation of such sites in cold regions.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3854-7
The tertiary spatial structure of biological macromolecules determines their physiological functions. In the formation of the tertiary structure, the secondary structure serves as the assembly foundation, and interactions between secondary structures play a critical role in driving and stabilizing the tertiary architecture. Synthetic foldamers, characterized by their modifiability and structural diversity, can adopt various helical conformations, enabling them to mimic natural protein secondary structures such as the α-helix, while also providing chemical models for studying interactions between secondary structures. This review outlines recent advances in aromatic foldamers and supramolecular helical assemblies formed by helical polymers, with particular attention to unique chiral phenomena observed during the formation of helical secondary structures. It provides a detailed summary of their applications in molecular recognition, ion channels, and circularly polarized luminescence, among others, and discusses future challenges facing aromatic foldamers. The review emphasizes the hierarchical nature of chirality—from primary atomic asymmetry to quaternary higher-order structures—and highlights the importance of understanding non-covalent interactions between helical secondary structures for regulating chiral assembly. Key strategies for constructing chiral helical aromatic foldamers include the use of chiral side chains, terminal groups, and solvent effects, as well as the sergeants-and-soldiers effect and majority-rules principle for chirality amplification. The applications of these foldamers in asymmetric catalysis, chiroptical materials, and biomimetic ion transport are also discussed, underscoring their potential in advanced functional materials.