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Small-angle X-ray scattering is used to probe the solution behavior of two similar electron donor polymers. Differences in aggregate crystallinity are observed upon cooling for the two polymers which is then correlated with the film morphology.

We report a novel elastomer possessing high stretchability, elasticity and self-healing ability, achieved by thio-β-diketone-Cu(ii) coordination and H-bonding dual crosslinking. Flexible sensors are fabricated based on the elastomer.

We report an asymmetric metal–ligand coordination strategy for reconfigurable elastomers. EXAFS is first introduced to monitor the structure change in M–L crosslinked polymers during stretching at the molecular level.

The report of the 19th National Congress of the Communist Party of China first proposed the strategy of rural revitalization. This proposal constitutes a major strategic deployment for work related to “agriculture, the countryside and farmers” based on China’s national and agricultural conditions and scientific analysis of the new problems faced by agricultural and rural reform in the new era. China’s agricultural development is facing multiple challenges, such as market competition, resource scarcity, environmental constraints, labor exodus, and technological innovation. Additionally, China’s agricultural production is inefficient, farmers’ income is low, and the hollowing out of the countryside has further intensified. To address these challenges, the Party Central Committee made the major decision to implement the rural revitalization strategy, and governments at all levels have introduced a series of policies to support agriculture. However, with the rapid advancement of industrialization and urbanization, the proportion of agricultural output to the total output of the national economy and the proportion of the agricultural labor force to the social labor force are not decreasing, and the idea of seizing the opportunities offered by agriculture is no longer able to solve the current dilemma faced by agricultural and rural development. Expanding the function of agriculture and actively docking with the industry and the service industry are a major strategic initiative for actively adapting to the new normal of economic development. They also represent major innovative thinking to accelerate the transformation of the agricultural development mode. Only when industries are prosperous can rural revitalization have a strong material foundation. To achieve industrial prosperity, industrial integration is the key. Therefore, the realization of rural industrial revitalization must take the path of industrial integration and development. At present, research on rural industrial integration is limited to the local regions, such as provinces and cities, and analysis at the level of national rural industrial integration is lacking. Accelerating the integrated development of rural industries is key to promoting rural revitalization. This paper scientifically establishes an evaluation index system for the level of rural industrial integration development based on five related aspects: society, the economy, resources, facilities, and the environment. Factor analysis is used to reduce the dimensionality of the evaluation index system, and cluster analysis is used to classify the rural industrial integration development level of each province in China into different tiers. The results show that there are obvious regional differences in the levels of rural industrial integration development in China. The provinces and cities with development levels that are higher than average (i.e., scores ranging from 0.291 to 0.915) are concentrated in the eastern coastal areas and inland riverine areas. In contrast, those with development levels that are lower than average (i.e., scores ranging from −0.504 to −0.750) are concentrated in Northern China, the northeastern noncoastal areas and northwestern areas. In addition, provinces can be divided into five development tiers of rural industrial integration. Based on this information, national, provincial, and municipal improvement strategies are proposed to address the differences in development among and the prospects for each province, and to effectively promote the integration of rural industries in China.

Humans rely increasingly on sensors to address grand challenges and to improve quality of life in the era of digitalization and big data. For ubiquitous sensing, flexible sensors are developed to overcome the limitations of conventional rigid counterparts. Despite rapid advancement in bench-side research over the last decade, the market adoption of flexible sensors remains limited. To ease and to expedite their deployment, here, we identify bottlenecks hindering the maturation of flexible sensors and propose promising solutions. We first analyze challenges in achieving satisfactory sensing performance for real-world applications and then summarize issues in compatible sensor-biology interfaces, followed by brief discussions on powering and connecting sensor networks. Issues en route to commercialization and for sustainable growth of the sector are also analyzed, highlighting environmental concerns and emphasizing nontechnical issues such as business, regulatory, and ethical considerations. Additionally, we look at future intelligent flexible sensors. In proposing a comprehensive roadmap, we hope to steer research efforts towards common goals and to guide coordinated development strategies from disparate communities. Through such collaborative efforts, scientific breakthroughs can be made sooner and capitalized for the betterment of humanity. Agency for Science, Technology and Research (A*STAR) National Research Foundation (NRF) Submitted/Accepted version Y.L., Z.L., M.Z., and X.C. acknowledge the National Research Foundation, Singapore (NRF) under NRF’s Medium Sized Centre: Singapore Hybrid-Integrated Next-Generation μElectronics (SHINE) Centre funding programme, and AME programming funding scheme of Cyber Physiochemical Interface (CPI) project (no. A18A1b0045). Y.L. acknowledges National Natural Science Foundation of China (62201243). C.J. acknowledges funding support from the National Key R&D Program of China (no. 2019YFA0706100), the National Natural Science Foundation of China (82151305), Lingang Laboratory (LG-QS-202202-09). T.Q.T. and N.E.L. acknowledge support by the Basic Science Research Program (no. 2020R1A2C3013480) through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT. A.F. acknowledges the AFOSR (grant FA9550-22-1-0423). Y.L. and Y.Z. would like to acknowledge the NSF (award no. 2134664) and NIH (award no. R01HD108473) for financial support. X.F. acknowledges the support from the National Natural Science Foundation of China (grant no. U20A6001). L.Y. would like to thank the A*STAR Central Research Fund (CRF) and the AME Programmatic A18A1b0045 (Cyber Physiochemical Interfaces) for funding support. C.F.G. acknowledges the National Natural Science Foundation of China (no. T2225017). T.Q.T. acknowledges the Brain Pool Program (No. 2020H1D3A2A02111068) through the National Research Foundation (NRF) funded by the Ministry of Science. Z.L. acknowledges the support from RIE2020 AME Programmatic Grant funded by A*STAR-SERC, Singapore (Grant No. A18A1b0045). X.G. acknowledges funding support through the Shanghai Science and Technology Commission (grant no. 19JC1412400), the National Science Fund for Excellent Young Scholars (grant no. 61922057). C.D. acknowledges National Science Foundation CAREER: Conformable Piezoelectrics for Soft Tissue Imaging (grant no. 2044688) and MIT Media Lab Consortium funding. D.K. and O.G.S. acknowledge Leibniz Association and the German Research Foundation DFG (Gottfried Wilhelm Leibniz Program SCHM 1298/22-1, KA5051/1-1 and KA 5051/3-1), as well as the Leibniz association (Leibniz Transfer Program T62/2019). C.W. acknowledges the National Key Research and Development Program of China (grant no. 2021YFA1202600), National Natural Science Foundation of China (grant no. 62174082). A.V.-Y.T., E.Z., Y.Z., X.Z., and J.P. acknowledge the National Research Foundation, Singapore (NRF) under NRF’s Medium Sized Centre: Singapore Hybrid-Integrated Next-Generation μElectronics (SHINE) Centre funding programme, and AME programming funding scheme of Cyber Physiochemical Interface (CPI) project (no. A18A1b0045). R.Z. acknowledges National Natural Science Foundation of China (grant no. 51735007) and Beijing Natural Science Foundation (grant no. 3191001). N.M. acknowledges the support by JST PRESTO Grant Number JPMJPR20B7 and JST Adaptable and Seamless Technology transfer Program through Target-driven R&D (ASTEP) grant number JPMJTM22BK. C.P. acknowledges the Korean government (Ministry of Science and ICT, MSIT) (2022R1A4A3032923). M.W. acknowledges the National Key R&D Program of China under Grant (2021YFB3601200). X.Z. acknowledges National Natural Science Foundation of China (no. 62074029). S.X. acknowledges the 3M nontenured faculty award. T.-W.L. and D.-G.S. acknowledge the Pioneer Research Center Program through the National Research Foundation of Korea funded by the Ministry of Science, ICT & Future Planning (grant no. NRF-2022M3C1A3081211). C.T.L. would like to acknowledge support from the Institute for Health Innovation and Technology (iHealthtech), the MechanoBioEngineering Laboratory at the Department of Biomedical Engineering and the Institute for Functional Intelligent Materials (I-FIM) at the National University of Singapore (NUS). C.T.L. also acknowledges support from the National Research Foundation and A*STAR, under its RIE2020 Industry Alignment Fund − Industry Collaboration Projects (IAF-ICP) (grant no. I2001E0059) − SIA-NUS Digital Aviation Corp Lab and the NUS ARTIC Research (grant no. HFM-RP1). X.Y. acknowledges funding support by City University of Hong Kong (grant no. 9667221). T.X. and X.Z. acknowledge National Natural Science Foundation of China (22234006). B.C.K.T. acknowledges Cyber-Physiochemical Interfaces CPI, A*STAR A18A1b0045. H.G. acknowledges a research start-up grant (002479-00001) from Nanyang Technological University and the Agency for Science, Technology and Research (A*STAR) in Singapore. W.G. acknowledges National Science Foundation grant 2145802. D.J.L. acknowledges support from the US National Science Foundation grant number CBET-2223566. G.Y. acknowledges support from The Welch Foundation award F-1861, and Camille Dreyfus Teacher-Scholar Award. M.D.D. acknowledges funding support from NSF (grant no. EEC1160483). J.-H.A acknowledges the National Research Foundation of Korea (NRF-2015R1A3A2066337). J.C. acknowledges the Henry Samueli School of Engineering & Applied Science and the Department of Bioengineering at the University of California, Los Angeles for startup support and a Brain & Behavior Research Foundation Young Investigator Grant. K.T. acknowledges JST AIP Accelerated Program (no. JPMJCR21U1) and JSPS KAKENHI (grant no. JP22H00594). P.S.W. acknowledges the National Science Foundation (CMMI1636136) for support. A.M.A., M.C.H., and P.S.W. thank the National Institute on Drug Abuse (DA045550) for support. S.M. and X.C. appreciated the support from the Smart Grippers for Soft Robotics (SGSR) Programme under the National Research Foundation, Prime Minister’s Office, Singapore under its Campus of Research Excellence and Technological Enterprise (CREATE) programme.

Flower-like polyacrylonitrile (PAN) particles have shown promising performance for numerous applications, including sensors, catalysis, and energy storage. However, the detailed formation process of these unique structures during polymerization has not been investigated. Here, we elucidate the formation process of flower-like PAN particles through a series of in situ and ex situ experiments. We have the following key findings. First, lamellar petals within the flower-like particles were predominantly orthorhombic PAN crystals. Second, branching of the lamellae during the particle formation arose from PAN's fast nucleation and growth on pre-existing PAN crystals, which was driven by the poor solubility of PAN in the reaction solvent. Third, the particles were formed to maintain a constant center-to-center distance during the reaction. The separation distance was attributed to strong electrostatic repulsion, which resulted in the final particles' spherical shape and uniform size. Lastly, we employed the understanding of the formation mechanism to tune the PAN particles' morphology using several experimental parameters including incorporating comonomers, changing temperature, adding nucleation seeds, and adjusting the monomer concentration. These findings provide important insights into the bottom-up design of advanced nanostructured PAN-based materials and controlled polymer nanostructure self-assemblies.

Recent work in structure–processing relationships of polymer semiconductors have demonstrated the versatility and control of thin-film microstructure offered by meniscusguided coating (MGC) techniques. Here, we analyze the qualitative and quantitative aspects of solution shearing, a model MGC method, using coating blades augmented with arrays of pillars. The pillars induce local regions of high strain rates—both shear and extensional—not otherwise possible with unmodified blades, and we use fluid mechanical simulations to model and study a variety of pillar spacings and densities. We then perform a statistical analysis of 130 simulation variables to find correlations with three dependent variables of interest: thin-film degree of crystallinity and transistor field-effect mobilities for charge-transport parallel (Μpara) and perpendicular (Μperp) to the coating direction. Our study suggests that simple fluid mechanical models can reproduce substantive correlations between the induced fluid flow and important performance metrics, providing a methodology for optimizing blade design. Polymer semiconductors have opened up a new frontier of electronics that can be flexible, stretchable, implantable, or biodegradable. While the chemical and electronic properties of these materials are important for their function as the active material in organic electronic devices, the manner by which these organic semiconductors are deposited onto a substrate can significantly influence its charge-transport properties. While a variety of techniques have been investigated to enhance charge-transport behavior, there are few reports approaching the issue in terms of the fluid dynamical considerations relevant during deposition from the solution phase. In this article, we analyze the fluid flow that occurs during thin-film deposition by solution shearing, a representative meniscusguided coating method amenable to high-throughput processing. We investigate a variety of variables related to fluid flow that can be estimated from fluid mechanical simulations of solution shearing with a coating blade patterned with a regular array of pillars used to induce higher fluid strain rates. We find correlations suggestive of underlying relationships between strain rates associated with certain directions and polymer charge-transport properties in the final deposited film. This article establishes a statistical approach using simulation data that can guide patterned blade design to enhance polymer deposition and realize high-performance devices.

Land circulation can promote large-scale operations, improve land-use efficiency, and increase farmers’ income. Taking 186 rural households in Ledong County in Hainan Province, the study uses binary logistic regression to analyze the factors affecting farmers’ willingness to transfer land. The results show that age, education level, and family labor force were negatively correlated with farmers’ willingness to accept land circulation. Meanwhile, gender, nonagricultural population, source of family income, annual family income, infrastructure, and understanding of policy were positively correlated with willingness to transfer. Recommendations regarding strengthening the training and education of farmers, increasing publicity, improving farmers’ awareness of land circulation, promoting market supervision, enhancing the land circulation market mechanism, and improving the rural security system are proposed. Ledong should also strengthen policy support regarding the cultivation of new agricultural business entities, and establish an intermediary service platform for land circulation. This study, therefore, aims to provide a theoretical and practical basis for a farmland circulation mechanism and the large-scale operation of agricultural land in Ledong County.

Combining the acceptor–donor–acceptor-type fused ring-based molecular architecture into a polymeric backbone is a promising strategy to design polymer acceptors for high-performance all-polymer sol...

Polymeric materials in nature regularly employ ordered, hierarchical structures in order to perform unique and precise functions. Importantly, these structures are often formed and stabilized by the cooperative summation of many weak interactions as opposed to the independent association of a few strong bonds. Here, we show that synthetic, flexible polymer chains with periodically placed and directional dynamic bonds collectively assemble into supramolecular nanofibers when the overall molecular weight is below the polymer's critical entanglement molecular weight. This causes bulk films of long polymer chains to have faster dynamics than films of shorter polymer chains of identical chemical composition. The formation of nanofibers increases the bulk film modulus by over an order of magnitude and delays the onset of terminal flow by more than 100 °C, while still remaining solution processable. Systematic investigation of different polymer chain architectures and dynamic bonding moieties along with coarse-grained molecular dynamics simulations illuminate governing structure-function relationships that determine a polymer's capacity to form supramolecular nanofibers. This report of the cooperative assembly of multivalent polymer chains into hierarchical, supramolecular structures contributes to our fundamental understanding of designing biomimetic functional materials.

Semitransparent organic photovoltaic cells (ST-OPVs) are emerging as a solution for solar energy harvesting on building facades, rooftops, and windows. However, the trade-off between power-conversion efficiency (PCE) and the average photopic transmission (APT) in color-neutral devices limits their utility as attractive, power-generating windows. A color-neutral ST-OPV is demonstrated by using a transparent indium tin oxide (ITO) anode along with a narrow energy gap nonfullerene acceptor near-infrared (NIR) absorbing cell and outcoupling (OC) coatings on the exit surface. The device exhibits PCE = 8.1 ± 0.3% and APT = 43.3 ± 1.2% that combine to achieve a light-utilization efficiency of LUE = 3.5 ± 0.1%. Commission Internationale d’eclairage chromaticity coordinates of (0.38, 0.39), a color-rendering index of 86, and a correlated color temperature of 4,143 K are obtained for simulated AM1.5 illumination transmitted through the cell. Using an ultrathin metal anode in place of ITO, we demonstrate a slightly green-tinted ST-OPV with PCE = 10.8 ± 0.5% and APT = 45.7 ± 2.1% yielding LUE = 5.0 ± 0.3% These results indicate that ST-OPVs can combine both efficiency and color neutrality in a single device.

Next-generation light-emitting displays on skin should be soft, stretchable and bright

In order to apply polymer semiconductors to stretchable electronics, they need to be easily deformed under strain without being damaged. A small number of conjugated polymers, typically with semicrystalline packing structures, have been reported to exhibit mechanical stretchability. Herein, a method is reported to modify polymer semiconductor packing-structure using a molecular additive, dioctyl phthalate (DOP), which is found to act as a molecular spacer, to be inserted between the amorphous chain networks and disrupt the crystalline packing. As a result, large-crystal growth is suppressed while short-range aggregations of conjugated polymers are promoted, which leads to an improved mechanical stretchability without affecting charge-carrier transport. Due to the reduced conjugated polymer intermolecular interactions, strain-induced chain alignment and crystallization are observed. By adding DOP to a well-known conjugated polymer, poly[2,5-bis(4-decyltetradecyl)pyrrolo[3,4-c]pyrrole-1,4-(2H,5H)-dione-(E)-1,2-di(2,2'-bithiophen-5-yl)ethene] (DPPTVT), stretchable transistors are obtained with anisotropic charge-carrier mobilities under strain, and stable current output under strain up to 100%.

Shape memory polymers are promising materials in many emerging applications due to their large extensibility and excellent shape recovery. However, practical application of these polymers is limited by their poor energy densities (up to ∼1 MJ/m3). Here, we report an approach to achieve a high energy density, one-way shape memory polymer based on the formation of strain-induced supramolecular nanostructures. As polymer chains align during strain, strong directional dynamic bonds form, creating stable supramolecular nanostructures and trapping stretched chains in a highly elongated state. Upon heating, the dynamic bonds break, and stretched chains contract to their initial disordered state. This mechanism stores large amounts of entropic energy (as high as 19.6 MJ/m3 or 17.9 J/g), almost six times higher than the best previously reported shape memory polymers while maintaining near 100% shape recovery and fixity. The reported phenomenon of strain-induced supramolecular structures offers a new approach toward achieving high energy density shape memory polymers., We report an approach to achieve a high energy density shape memory polymer based on the formation of strain-induced supramolecular nanostructures, which immobilize stretched chains to store entropic energy.

The ability to deposit polymer semiconductors (PSCs) over a large area at near-ambient conditions makes them exciting candidates for low-cost, large-area electronic applications. Given the sensitiv...

Summary Advances in stretchable conductors have been one of the main driving forces behind the realization of wearable and epidermal electronics. However, retaining constant strain-property relationships under varying strain and strain rate remains a challenge. Here, we demonstrate a 3D structuring approach toward strain-accommodating, biocompliant conductors. In contrast to previous stretchable conductors, this method leads to polymeric materials with conductance that has zero dependence on (1) both tensile and compressive strain over an 80% strain range, and (2) strain rate from 2.5%/min to 2,560%/min. Their Young's moduli can be controllably tuned between 10 and 300 kPa. In addition, these conductors are ultra-lightweight and can be molded into virtually any shape and size. Their properties mimic the dynamic and softness of biological systems, rendering this a versatile platform for designing electronic materials that can potentially form intimate interfaces with humans.

The field of organic electronics aspires to enable the fabrication of low-cost, solution-processed optoelectronic devices with unique mechanical, electrical, optical, and chemical properties. Criti...

All-polymer solar cells (all-PSCs) are the most promising power generators for flexible and portable devices due to excellent morphology stability and outstanding mechanical property. Previous work indicates high crystallinity is beneficial to device performance but detrimental to mechanical property, therefore identifying the optimized ratio between crystalline and amorphous domains becomes important. In this work, we demonstrated highly efficient and mechanically robust all-PSCs by blade-coating technology in ambient environment based on PTzBI:N2200 system. By controlling the aggregation in solution state and ultrafast film formation process, a weakly ordered molecular packing morphology as well as small phase separation is obtained, which leads to not only the good photovoltaic performance (8.36%-one of the best blade-cast device in air) but also prominent mechanical characteristic. The controlled film shows a remarkable elongation with the crack onset strain of 15.6%, which is the highest result in organic solar cells without adding elastomers. These observations indicate the great promise of the developed all-PSCs for practical applications toward large-area processing technology.

Supramolecular polymer sorting is a promising approach to separating single-walled carbon nanotubes (CNTs) by electronic type. Unlike conjugated polymers, they can be easily removed from the CNTs after sorting by breaking the supramolecular bonds, allowing for isolation of electronically pristine CNTs as well as facile recycling of the sorting polymer. However, little is understood about how supramolecular polymer properties affect CNT sorting. Herein, chain stoppers are used to engineer the conformation of a supramolecular sorting polymer, thereby elucidating the relationship between sorting efficacy and polymer conformation. Through NMR and UV-vis spectroscopy, small-angle X-ray scattering (SAXS), and thermodynamic modeling, it is shown that this supramolecular polymer exhibits ring-chain equilibrium, and that this equilibrium can be skewed toward chains by the addition of chain stoppers. Furthermore, by controlling the stopper-monomer ratio, the sorting yield can be doubled from 7% to 14% without compromising the semiconducting purity (>99%) or properties of sorted CNTs.

Doping of organic semiconductors is a powerful tool to optimize the performance of various organic (opto)electronic and bioelectronic devices. Despite recent advances, the low thermal stability of the electronic properties of doped polymers still represents a significant obstacle to implementing these materials into practical applications. Hence, the development of conducting doped polymers with excellent long-term stability at elevated temperatures is highly desirable. Here, we report on the sequential doping of the ladder-type polymer poly-(benzimidazobenzophenanthroline) (BBL) with a benzimidazole-based dopant (i.e., N-DMBI). By combining electrical, UV-vis/infrared, X-ray diffraction, and electron paramagnetic resonance measurements, we quantitatively characterized the conductivity, Seebeck coefficient, spin density, and microstructure of the sequentially doped polymer films as a function of the thermal annealing temperature. Importantly, we observed that the electrical conductivity of N-DMBI-doped BBL remains unchanged even after 20 h of heating at 190 degrees C. This finding is remarkable and of particular interest for organic thermoelectrics. Funding Agencies|Swedish Research CouncilSwedish Research Council [2016-03979]; AForsk [18-313, 19310]; Olle Engkvists Stiftelse [204-0256]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]; Finnish Cultural FoundationFinnish Cultural Foundation; Finnish Foundation for Technology Promotion; Knut and Alice Wallenberg FoundationKnut & Alice Wallenberg Foundation; Knut and Alice Wallenberg FoundationKnut & Alice Wallenberg Foundation [Dnr KAW 2014.0041]

Different temperatures, solvents, and additives are used as influencing parameters to drive molecular packing and phase separation for the development of the controlled evolution of nanostructures for organic solar cells (OSCs). The temperature-dependent aggregation (TDA) features of polymers are explored by investigating aggregation in solution and solid thin-film states using solution small-angle neutron scattering (SANS), soft/hard X-ray scattering, and transmission electron microscopy (TEM) characterizations. In situ grazing incidence wide angle X-ray scattering (GIWAXS) reveals that the nucleation process is highly significant and responsible for the ultimate film morphology. Processing conditions such as temperatures, solvents, and additives were used to influence the nucleation and evolution of film morphology. The nucleation process may improve the polymer packing and phase separation. It may translate into optimized multilength scale domains and efficient charge percolation pathways, a strong imp...

The emergence of wearable electronics puts batteries closer to the human skin, exacerbating the need for battery materials that are robust, highly ionically conductive, and stretchable. Herein, we introduce a supramolecular design as an effective strategy to overcome the canonical tradeoff between mechanical robustness and ionic conductivity in polymer electrolytes. The supramolecular lithium ion conductor utilizes orthogonally functional H-bonding domains and ion-conducting domains to create a polymer electrolyte with unprecedented toughness (29.3 MJ m−3) and high ionic conductivity (1.2 × 10−4 S cm−1 at 25 °C). Implementation of the supramolecular ion conductor as a binder material allows for the creation of stretchable lithium-ion battery electrodes with strain capability of over 900% via a conventional slurry process. The supramolecular nature of these battery components enables intimate bonding at the electrode-electrolyte interface. Combination of these stretchable components leads to a stretchable battery with a capacity of 1.1 mAh cm−2 that functions even when stretched to 70% strain. The method reported here of decoupling ionic conductivity from mechanical properties opens a promising route to create high-toughness ion transport materials for energy storage applications., Typically, ion conducting polymers exhibit a trade-off between mechanical robustness and ionic conducting performance. Here, the authors utilize supramolecular chemistry obtaining extremely tough electrolytes with high ionic conductivity and enabling stretchable lithium-ion batteries.