Chemically crosslinked polyacrylamide (PAAm) nanocomposite hydrogels were prepared with inorganic nano-silicate, Laponite, and dopamine methacrylamide (DMA). DMA consists of a biomimetic adhesive side chain covalently linked to a polymerizable methacrylate monomer. Copolymerizing DMA into a PAAm hydrogel strongly enhanced the interfacial interaction between the polymer network and Laponite. Nanocomposite hydrogels demonstrated reduced water content and increased materials properties that were dependent on both the Laponite and DMA contents. While increasing Laponite content alone improved materials properties moderately, these improvements were drastically enhanced when DMA is incorporated as measured by both unconfined compression testing and oscillatory rheometry. DMA-containing nanocomposite hydrogels demonstrated increased stiffness as well as excellent energy dissipation capability. Nanocomposite hydrogels with relatively low DMA and Laponite contents (2 to 3 wt% for each) demonstrated maximum compressive stress, elastic modulus, toughness, and storage and loss moduli values that were over an order of magnitude higher than control gels.DMA-containing nanocomposite hydrogels also demonstrated improved fracture resistance to compressive loading, capable of repeated compressed to 80% strain without rest for over 10 times while exhibiting compressive stress of over 1.1 MPa. The catechol side chain of DMA likely formed strong physical bonds with Laponite, which can dissipate fracture energy while minimizing permanent damage to the network architecture.

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Background: Blacks are dying from the novel coronavirus of 2019 (COVID-19) at disproportionate rates and tend to have more COVID-19 vaccine hesitancy than Whites. These disparities may be attributable to health knowledge and government/medical mistrust stemming from negative experiences with the medical system historically and presently (e.g., the Tuskegee Experiment, provider maltreatment). Method: The present study assessed COVID-19 vaccine hesitancy and the effectiveness of a 1.5 h, dialogue-based, web intervention hosted by an academic–community partnership team. The webinar included approximately 220 male and female, English speaking, Black churchgoers in the western U.S. The webinar focused on the psychology of fear and facts about the vaccine development. Results: The sample was mostly females who had higher vaccine hesitancy than men. A third of participants feared hospitalization if they contracted COVID-19. Many participants reported that learning facts about COVID-19 was most impactful. Statistical analyses indicated an increased willingness to get vaccinated after the webinar in comparison to before (t(25) = −3.08, p = 0.005). Conclusion: The findings suggest that virtual webinars may be effective at reducing COVID-19 vaccine hesitancy among Black churchgoers and may be applicable in addressing other health behaviors.