Superrepellent surfaces, such as micro/nanostructured surfaces, are of key importance in both academia and industry for emerging applications in areas such as self-cleaning, drag reduction, and oil repellence. Engineering these surfaces is achieved through the combination of the required surface topography, such as porosity, with low-surface-energy materials. The surface topography is crucial for achieving high liquid repellence and low roll-off angles. In general, the combination of micro- and nanostructures is most promising in achieving high repellence. In this work, we report the enhancement of wetting properties of porous polymers by replication from wrinkled Parylene F (PF)-coated polydimethylsiloxane (PDMS). Fluorinated polymer foam “Fluoropor” serves as the low-surface-energy polymer. The wrinkled molds are achieved via the deposition of a thin PF layer onto the soft PDMS substrates. Through consecutive supercritical drying, superrepellent surfaces with a high surface porosity and a high water contact angle (CA) of >165° are achieved. The replicated surfaces show low roll-off angles (ROA) <10° for water and <21° for ethylene glycol. Moreover, the introduction of the micro-wrinkles to Fluoropor not only enhances its liquid repellence for water and ethylene glycol but also for liquids with low surface tension, such as n-hexadecane.

Understanding the wettability of soft surfaces is of key importance for the development of protective and repellent coatings and controlling droplet dynamics when required. There are many factors that affect the wetting and dynamic dewetting behavior of soft surfaces, such as the formation of wetting ridges, the adaptive behavior of the surface caused by the interaction of the fluid with the surface, or the presence of free oligomers that are washed out of the soft surface. In this work, we report the fabrication and characterization of three soft polydimethylsiloxane (PDMS) surfaces with elastic moduli ranging from 7 kPa to 56 kPa. The dynamic dewetting behavior of liquids with different surface tensions was studied on these surfaces, and the data show soft and adaptive wetting behavior of the soft PDMS, as well as the presence of free oligomers. Thin layers of Parylene F (PF) were introduced to the surfaces and their influence on the wetting properties was studied. We show that the thin layers of PF prevent adaptive wetting by preventing the diffusion of liquids into the soft PDMS surfaces and by causing the loss of the soft wetting state. The dewetting properties of the soft PDMS are enhanced, leading to low sliding angles of ≤10° for water, ethylene glycol, and diiodomethane. Therefore, the introduction of a thin PF layer can be used to control wetting states and to increase the dewetting behavior of soft PDMS surfaces.

Atrial fibrillation is an irregular heart rhythm, and it is one of the most common cardiac arrhythmias. It is associated with a five times increase in the risk of stroke. Anti-coagulants are prescribed routinely to prevent strokes, especially in patients with atrial fibrillation for many years decreasing the risk of stroke among patients with atrial fibrillation. Non-vitamin K oral anticoagulants especially apixaban and rivaroxaban are frequently used and they are considered to be safe and more effective than warfarin. The aim of this metaanalysis is to compare the efficacy and safety of apixaban and warfarin in preventing stroke among patients with non-valvular arterial fibrillation. The current meta-analysis was conducted using the guidelines established by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). A systematic search was done using databases, including PubMed, EMBASE, and Cochrane Library, with no restrictions on language and year of publication. The current meta-analysis included randomized control trials and non-randomized control trials (prospective and retrospective cohort studies) comparing the efficacy and safety of apixaban and warfarin in preventing stroke in patients with non-valvular atrial fibrillation. The primary efficacy outcome was stroke or systemic embolism while the primary safety outcome was major bleeding events. Overall, nine articles were included in the current meta-analysis with a pooled sample size of 267998 patients with non-valvular atrial fibrillation. The administration of apixaban was associated with a significant decrease in stroke or systemic embolism (RR: 0.77, 95% CI: 0.67-0.90) and major bleeding events (RR=0.63, 95% CI: 0.58-0.68) as compared to warfarin. However, no significant difference was reported in all-cause mortality (RR=0.80, 95% CI: 0.30-2.14) between the two groups. The current meta-analysis concluded that apixaban, compared to warfarin in patients with non-valvular atrial fibrillation showed a reduction in stroke and systemic embolism. Apixaban has also a better safety profile in terms of reduction in overall major bleeding events.

No abstract