The primary research question of the paper explores how the photodegradation of phenyl vinyl ketone (PVK) polymer nanoparticles under UV light affects their self-assembled morphologies, surface properties, and capabilities for molecular encapsulation and release. Specifically, the researchers investigate the morphological stability and reversal of different initial nanoparticle shapes, analyzing why spheres and vesicles maintain their structure over long periods despite molecular weight drops, while worm-shaped nanoparticles quickly revert to spheres. Additionally, the study examines how these degradation processes and the resulting shape changes alter the surface properties of nanoparticle coatings. Ultimately, the authors seek to determine if these photo-responsive nanoparticles can effectively encapsulate and strategically release molecules, with the broader goal of leveraging these conversion-dependent behaviors for smart material systems like agrochemical delivery, cleaning agents, and targeted surface modifications.

The results of the study demonstrate that exposing the phenyl vinyl ketone (PVK) polymer nanoparticles to UV light triggers Norrish Type II backbone cleavage, leading to significant, shape-dependent morphological transformations. Specifically, the findings reveal that worm-like nanoparticles rapidly reverse their morphology into spheres within just two minutes of irradiation, whereas spherical and vesicular structures display remarkable resilience by maintaining their shapes for up to 24 hours due to the trapping of hydrophobic polymer fragments. Beyond these structural changes, the research confirms that this targeted degradation process successfully alters the surface hydrophobicity of the materials and facilitates the controlled release of encapsulated payloads. Ultimately, these findings suggest that the initial thermodynamic state of the nanoparticle dictates its responsiveness to light, establishing these PVK-based systems as a highly versatile and tunable platform with promising applications in smart coatings, precision therapeutic delivery, and other responsive material technologies.

This work was supported by the National Science Foundation under award number CHE-2203727. The authors would like to acknowledge Dr. Zachery Oestreicher and resources from the Center for Advanced Microscopy and Imaging (CAMI) at Miami University, Dr. Anne Carroll for the assistance in NMR at Miami University, Dr. Steven Keller at Miami University for assistance with contact angle measurements, Dr. Andrea Kravats at Miami University for assistance with UV absorbance measurements, and Bryan McLean from the undergraduate organic laboratories at Miami University for providing 9-fluorenone. The authors declare no conflict of interest.

Through extensive laboratory research spanning four academic years and two summers, I have significantly developed key career readiness competencies, particularly in critical thinking, communication, technology, and professionalism. My analytical skills have been honed by tackling complex chemical derivations and rigorously validating empirical data, such as independently calculating precise enzyme kinetic values rather than relying on assumed outputs. I have also cultivated strong communication skills by translating intricate findings on nanoparticle photodegradation into compelling formats, successfully distilling months of work into a concise eight-minute poster presentation and detailed funding abstracts. Furthermore, I have gained hands-on technological proficiency by mastering advanced instrumentation—such as NMR, GPC, TEM, and DLS—to conduct rigorous material characterization. Ultimately, navigating the iterative challenges of multi-step polymer synthesis over several years has instilled a deep sense of resilience and professional accountability, allowing me to successfully drive a complex research project from its initial stages to a polished final presentation.