The growing popularity of smart electronics in wearables, the Internet of Things (IoT), soft robotics, and biomedical implants simultaneously demands more reliable and durable power sources. However, limitations on battery life continue to compromise reliability, prompting the search for sustainable solutions for flexible, self-powered systems. In this work, stretchable self-powered piezoelectric nanogenerators have been designed from functionalized piezoelectric nanofibers with a bioinspired coiled helical microstructure. Composed of two-dimensional (2D) Ti₃C₂T_x MXene and silver nanoparticles (AgNPs) embedded in a poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) matrix, the coiled structure achieves a mechanoelectrical energy conversion efficiency of 17%, and a power output of 6.6 mW cm⁻³ at 50% strain, twice the performance of similarly coiled structures. These improvements were attributed to the threefold increase in the piezoelectric coefficient through the addition of 1 wt% AgNPs to the P(VDF-TrFE)/MXene (0.1 wt%) and the coiled structure further enhancing β-phase formation reaching up to 70%. An electrospun mat sensor with dimensions of 2 × 3 cm generated 3 V at 1 Hz under an applied pressure of 7 kPa. The coil compact and lightweight design enables seamless integration into miniaturized electronics and wearable biomedical devices, promising a sustainable, battery-free power solution.

Nucleation, the pivotal first step of crystallization, governs the essential characteristics of crystallization products, including size distribution, morphology, and polymorphism. While understanding this process is paramount to the design of chemical, pharmaceutical, and industrial production processes, major knowledge gaps remain, especially with respect to the crystallization of porous solids. Also for nanocrystalline ZIF-8, one of the most widely studied metal-organic frameworks, questions regarding the species involved in the nucleation pathway and their structural and chemical transformations remain unanswered. By combining harmonic light scattering, inherently sensitive to structural changes, with NMR spectroscopy, which reveals molecular exchanges between particles and solution, we were able to capture the crystallization mechanism of ZIF-8 in unprecedented detail. This dual approach provides concurrent structural and chemical insights, revealing key processes not previously observed in ZIF crystallization. Upon mixing, small charged prenucleation clusters (PNCs) are formed, exhibiting an excess of ligands and net positive charge. We show that nucleation is initiated by aggregation of PNCs, through the release of ligands and associated protons to the liquid. This leads to the formation of charge neutral amorphous precursor particles (APPs), which incorporate neutral monomers from the solution and crystallized ZIF-8. Our work highlights chemical dynamics as a vital, yet often overlooked, dimension in the multistage structural evolution of MOFs. By establishing the critical role of PNCs in the nucleation of ZIF-8, new pathways open up for controlling crystallization of metal-organic frameworks through targeted chemical interactions with these species.

Recent developments in nonlinear optical light scattering techniques have opened a window into morphological and structural characteristics for a variety of supramolecular systems. However, for the study of dynamic processes, the current way of measuring is often too slow. Here we present an alternative measurement scheme suitable for following dynamic processes. Fast acquisition times are achieved through Fourier imaging, allowing simultaneous detection at multiple scattering angles for different polarization combinations. This allows us to follow the crystal growth of the metal organic framework ZIF-8 in solution. The angle dependence of the signal provides insight into the growth mechanism by probing the evolution of size, shape and concentration, while polarization analysis yields structural information in terms of point group symmetry. Our findings highlight the potential of dynamic angle-resolved harmonic light scattering to probe crystal growth processes, assembly–disassembly of biological systems, adsorption, transport through membranes and myriad other applications.