Xingyou Tian

To explain the single and wide first-order long-period peak observed in semicrystalline polymers, classical small-angle X-ray scattering (SAXS) theory regards the dispersity in lamellar thickness/long period as the key structural feature of semicrystalline polymers. Other factors affecting the SAXS pattern such as the lateral size of a lamellar stack, the number of lamellar crystals in a stack and linear crystallinity have been overlooked as secondary factors, preventing structure extraction from SAXS. In this study, we attempted to establish a scattering equation for semicrystalline polymers formed during quiescent crystallization without considering dispersity in the long period/lamellar thickness. The results indicate that the lateral size is the key factor leading to the unique SAXS pattern in semicrystalline polymers and the absence of the linear region in the correlation function. SAXS in semicrystalline polymers results from minor lamellar stacks with small intersection angles with the incident X-rays. On the basis of the results, we suggest employing a revised interface distribution function to obtain structural information after recovering higher-order weak long-period peaks by a difference method. Half of the q ⁴ correction is to eliminate the influence of the form factor, while the other half is to remove the factor of 1/ q ² in the structure factor. This study helps to further our understanding of SAXS in semicrystalline polymers.

The presence of supramolecular interactions plays a crucial role in the formation of resilient multifunctional elastomers. Nevertheless, achieving elastomers with fabulous mechanical properties remains a significant challenge due to the incomplete understanding of the underlying principles. In this study, we have presented a simple yet efficient approach for manipulating the microstructure, resulting in a significant enhancement of the mechanical properties of the elastomers. By utilizing hydrophobic and hydrophilic extended chain segments to elongate a hydrophilic oligomer, we successfully created elastomers with improved toughness and stiffness through supramolecular interactions. The elastomer with hydrophobic extended chain segments demonstrates a fracture energy (94 842 J m⁻²) and high tensile stress (16 MPa). In contrast, the elastomer with hydrophilic extended segments showed significantly lower tensile stress (0.18 MPa), even though their molecular chain structures are nearly identical. We conducted a systematic demonstration and investigation of the significant difference mentioned above and ultimately found that due to the hydrophobic–hydrophilic difference between the oligomer and extended chain segments, the hydrophobic chain segments are able to create hydrophobic association and the association can further facilitate the development of stronger and more abundant supramolecular interactions (hydrogen bonds). The resulting hydrogen bonds, combined with the hydrophobic association, effectively disperse energy and consequently improve the elastomer's capacity to withstand external forces. The hydrophilic–hydrophobic mechanism showcases the potential for creating durable supramolecular materials with promising applications in biology and electronics.

Correction for ‘Superhydrophobic and mechanical properties enhanced the electrospinning film with a multiscale micro-nano structure for high-efficiency radiation cooling’ by Lijing Kong et al. , J. Mater. Chem. A , 2024, https://doi.org/10.1039/D3TA07191J.

To date, although radiation cooling technology has made some progress in numerous aspects, significant challenges remain in terms of efficient cooling and practical applications. Herein, we report the preparation of a polyvinylidene fluoride (PVDF) composite film with a multiscale micro-nano structure, in which zirconia (ZrO₂) particles were bonded on the surface of the PVDF fibers via polydimethylsiloxane (PDMS). This PVDF composite film showed a relatively high solar reflectivity (>0.95) and excellent emissivity (>0.96) in the infrared atmospheric window, which resulted in a 21.8 °C and 10.4 °C temperature reduction compared to the simulated skin and ambient temperature under direct sunlight of about 1000 W m⁻², respectively. Meanwhile, the combination of the multistage structure and hydrophobicity property of PDMS resulted in superhydrophobicity with a hydrophobic angle of 155° and sliding angle of about 5°, thereby conferring the film with exceptional self-cleaning ability. Notably, PDMS simultaneously facilitated the formation of a bonding structure between the fibers, leading to enhanced mechanical properties. Compared to those of the PVDF electrospun film (F-S), the tensile strength and tensile strain of the designed composite film increased by 9.5 times and 4.4 times, respectively. Thus, the excellent performances of the PVDF composite film provide a great development prospect for the practical application of electrospun films in smart textiles and energy-saving.

Multiple H-bond networks and unique structures are designed in CCF/PDMS. This CCF/PDMS elastomer simultaneously exhibits excellent tensile, self-healing, and triboelectric properties, promising to be used in energy harvesters and motion sensors, etc.

Mixed lead‐tin (PbSn) perovskite solar cells (PSCs) possess low toxicity and adjustable bandgap for both single‐junction and all‐perovskite tandem solar cells. However, the performance of mixed PbSn PSCs still lags behind the theoretical efficiency. The uncontrollable crystallization and the resulting structural defect are important reasons. Here, the bidirectional anions gathering strategy (BAG) is reported by using Methylammonium acetate (MAAc) and Methylammonium thiocyanate (MASCN) as perovskite bulk additives, which Ac⁻ escapes from the perovskite film top surface while SCN⁻ gathers at the perovskite film bottom in the crystallization process. After the optoelectronic techniques, the bidirectional anions movement caused by the top‐down gradient crystallization is demonstrated. The layer‐by‐layer crystallization can collect anions in the next layer and gather at the broader, enabling a controllable crystallization process, thus getting a high‐quality perovskite film with better phase crystallinity and lower defect concentration. As a result, PSCs treated by the BAG strategy exhibit outstanding photovoltaic and electroluminescent performance with a champion efficiency of 22.14%. Additionally, it demonstrates excellent long‐term stability, which retains ≈92.8% of its initial efficiency after 4000 h aging test in the N₂ glove box.

In this study, the performance of low-temperature sintered Bi-B-Si-Zn-Al glass/SiC composites by vacuum hot-press sintering between 700°C and 1000°C was investigated. The specimen had a relatively preferable density of 95.5% and thermal conductivity of 8.660 Wm⁻¹K⁻¹ after sintering at 900°C for 2 h. The dielectric constant and dielectric loss tangle of the composite were 32.9 and 0.57 at 20 GHz, respectively. The XRD analysis indicated the formation of Bi, Zn and ZnAl₂O₄ crystals, and the microstructure showed the low contact angle of the glass and SiC grain. Such low-temperature sintered SiC ceramic may have a promising application in the electronic field.