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  • Solution-state nanoconfined aggregation and microstructure evolution in blends of conjugated polymers and elastomers. Proceedings of the National Academy of Sciences of the United States of America Peña-Alcántara, A. E., Ghasemi, M., Cheng, C., Chaney, T. P., Coffey, A. H., Ponte, E., Ji, X., Michalek, L., Wu, Y., Schrock, M., Ngaruka, G., Gala, M. L., Zhu, C., Toney, M. F., Salleo, A., Gomez, E. D., Bao, Z. 2026; 123 (18): e2516186123

    Abstract

    Emerging wearable health monitoring technologies require conformable and stretchable devices. Polymer semiconductors composed of π-conjugated polymer aggregates in an elastomeric matrix are remarkable in their ability to provide both high stretchability and enhanced charge transport. Understanding their film formation process is critical in improving charge transport, imparting added functionalities, and advancing large-scale production of high-performing polymer electronic devices. Here, using a poly-thieno[3,2-b]thiophene-diketopyrrolopyrrole (DPPTT): polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) blend as a model system, electron tomography of the blend reveals the presence of bundles of conjugated polymer nanofibers spanning the thickness of the films. High-resolution cryogenic electron microscopy (cryo-EM) of solution and thin films reveals that the nanoconfined DPPTT nanofibers in blends are composed of the aligned DPPTT 1D aggregates present in solution. In contrast, neat DPPTT solutions and thin films contain irregular crystalline domains with random orientations. In situ grazing incidence wide-angle X-ray scattering (GIWAXS) studies reveal that DPPTT crystallization commences earlier in blends compared to neat films. Combining observations from both in situ ultraviolet-visible spectroscopy, in situ GIWAXS and cryo-EM reveal that 1D aggregates in blend solution bundle and align into interconnected larger fibers that are nanoconfined in the SEBS matrix. This morphology is desirable for efficient charge transport and good mechanical strength. In contrast, neat DPPTT films contain randomly oriented smaller aggregates with an increased fraction of disordered domains. Overall, our work provides critical insights on the impact of solution composition and processing conditions on thin film morphology for achieving multifunctional high-performing electronic polymer composites.

    View details for DOI 10.1073/pnas.2516186123

    View details for PubMedID 42030140

  • A guide for nanomechanical characterization of soft matter via AFM: From mode selection to data reporting. STAR protocols Kim, E., Ramos Figueroa, A. L., Schrock, M., Zhang, E., Newcomb, C. J., Bao, Z., Michalek, L. 2025; 6 (2): 103809

    Abstract

    Atomic force microscopy (AFM) enables high-resolution mechanical characterization of soft materials at the nanoscale. It offers unique advantages over conventional mechanical testing methods by providing spatially resolved properties, requiring minimal sample preparation, and allowing measurements under controlled environmental conditions. This comprehensive guide provides a practical framework for conducting reproducible nanomechanical measurements on soft matter using AFM. Readers will learn how to select appropriate AFM modes, choose and calibrate suitable cantilevers, prepare samples, and optimize measurement parameters for soft materials. Four operational AFM modes are described: intermittent contact mode, nanomechanical imaging, force modulation, and force spectroscopy. We detail their principles, mechanisms, and trade-offs while offering practical advice for experiment execution, data analysis, and result reporting. This protocol seeks to guide researchers to execute consistent and comparable AFM measurements, bridge the gap between theoretical knowledge and practical implementation, and address key challenges in standardization and reproducibility within the field of soft matter nano-mechanics.

    View details for DOI 10.1016/j.xpro.2025.103809

    View details for PubMedID 40449004

  • Tuning the Mobility of Indacenodithiophene-Based Conjugated Polymers via Coplanar Backbone Engineering CHEMISTRY OF MATERIALS Ji, X., Cheng, H., Schuster, N. J., LeCroy, G. S., Zhang, S., Wu, Y., Michalek, L., Nguyen, B. T., Chiong, J. A., Schrock, M., Tomo, Y., Rech, J., Salleo, A., Gam, S., Lee, G., Tok, J., Bao, Z. 2023; 36 (1): 256-265

    View details for DOI 10.1021/acs.chemmater.3c02006

    View details for Web of Science ID 001139519300001

https://orcid.org/0000-0002-5946-8893