Pollen Films
Next Generation Possibilities
What are Pollen Films?
Pollen films are thin, flexible materials derived from natural pollen grains that retain the unique properties of pollen microgels, such as mechanical robustness, biodegradability, and responsiveness to environmental stimuli. They are composed primarily of hollow pollen microgels that undergo structural collapse and flattening during the dehydration of pollen microgel slurry on a flat casting mold. The stacking of these flattened pollen discs inherently results in a layered continuous sheet structure, an asymmetric surface micromorphology, conferring unique properties rarely seen in other polymer materials such hydro-sensing capability and stimuli-responsive swelling and shrinking.
Pollen films offer an eco-friendly alternative to synthetic materials. They can be engineered to be strong, flexible, and lightweight while having the ability to change physical dimensions in response to humidity or pH. Through controlled processing, allergenic proteins can be removed, making pollen sheets safe for various biological applications. The properties of pollen film can be tailored for different mechanical, optical, or chemical properties simply by altering the microgel synthesis conditions.
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"Actuation and Locomotion Driven by Moisture in Paper Made with Natural Pollen." PNAS 2020; 117, 16, 8711-8718.
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Digital printing of shape-morphing natural materials
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Recyclable and Reusable Natural Plant-Based Paper for Repeated Digital Printing and Unprinting
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Multifunctional Material Building Blocks from Plant Pollen


How are Pollen Films and thin substrates made?
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Synthesis of pollen microgels from raw pollen
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Preparation and casting of pollen microgel suspension on a flat mold
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Drying off of excess moisture at ambient conditions to yield a peelable film
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For multilayered substrates/papers, hot pressing of multiple pollen films is performed

What are the other type of pollen explored?
Pollen species from sunflowers are usually utilized in the pollen film synthesis because of their superior gelling propensity and stronger pH responsiveness compared to other pollen species. Pollen grains from camellia and lotus plants that have been proven to form microgels are also able to form pollen sheets with similar properties such as alkali-induced swelling, unprintability and recyclability

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Zhao, Z.; Deng, J.; Tae, H.; Ibrahim, M. S.; Suresh, S.; Cho, N. Recyclable and Reusable Natural Plant‐Based Paper for Repeated Digital Printing and Unprinting. Adv. Mater. 2022, 34 (19), 2109367.
What are the other possible applications of the pollen film?
Due to its unique properties such as mechanical flexibility, biodegradability, and responsiveness to external stimuli (e.g., pH, humidity, temperature), pollen films have several potential applications beyond just being a reusable and recyclable printing material.
Pollen film could be integrated into flexible and biodegradable electronic circuits for soft electronics & wearable devices , serving as a sustainable alternative for transient electronics, flexible batteries, and bio-based sensors. Its ability to respond to environmental changes (e.g., humidity, pH, or temperature) also makes it an excellent candidate for sensors used in health monitoring, environmental tracking, and food packaging applications. The biocompatibility and porosity of pollen paper may also allow it to be suitable for biomedical applications such as in tissue engineering and wound management. The substrate’s ability to undergo shape transformations under humidity variations could be harnessed for bioinspired soft robotic systems and self-folding structures. Furthermore. pollen films could be explored as a functional substrate for microfluidics, bioassays, and other lab-on-a-chip applications, offering a sustainable and responsive alternative to conventional synthetic materials.
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Multifunctional Material Building Blocks from Plant Pollen
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Zhao, Z.; Deng, J.; Tae, H.; Ibrahim, M. S.; Suresh, S.; Cho, N. Recyclable and Reusable Natural Plant‐Based Paper for Repeated Digital Printing and Unprinting. Adv. Mater. 2022, 34 (19), 2109367.
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Hwang, Y.; Kim, M. K.; Zhao, Z.; Kim, B.; Chang, T.; Fan, T. F.; Ibrahim, M. S.; Suresh, S.; Lee, C. H.; Cho, N.-J. Plant-Based Substrate Materials for Flexible Green Electronics. Adv. Mater. Technol. 2022, 7 (12), 2200446. https://doi.org/10.1002/admt.202200446.
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Zhao, Z.; Kumar, J.; Hwang, Y.; Deng, J.; Ibrahim, M. S. B.; Huang, C.; Suresh, S.; Cho, N.-J. Digital Printing of Shape-Morphing Natural Materials. Proc. Natl. Acad. Sci. 2021, 118 (43), e2113715118.