Soft substrates enhance droplet nucleation during water vapor condensation because their deformability inherently reduces the energetic threshold for heterogeneous nucleation relative to rigid substrates. However, this enhancement is counteracted later in the condensation cycle, when substrate viscoelastic dissipation inhibits condensate droplet shedding. Here a polydimethylsiloxane (PDMS) based organogel is designed to overcome this limitation. It is shown that merely 5% bulk lubricant infusion in PDMS reduces viscoelastic dissipation in the substrate by nearly 28 times while doubling the droplet nucleation density. Parameters for water condensation on this organogel are correlated with material properties controlled by design, i.e., fraction and composition of uncrosslinked chains and shear modulus. It is demonstrated that the increase in nucleation density and reduction in precoalescence droplet growth rate is rather insensitive to the lubricant percentage in PDMS within the broad range investigated. These results indicate the presence of a lubricant layer on the substrate surface that cloaks the growing condensate droplets. This cloaking effect is visualized, and it is shown that cloaking occurs significantly faster on PDMS if it is infused with bulk lubricant. Overall, bulk lubricant infusion in PDMS enhances condensation and leads to a more than 40% higher dewing on the substrate.

Most climate change mitigation scenarios restricting global warming to 1.5 oC rely heavily on Negative Emissions Technologies and Practices (NETPs). Here we updated previous literature reviews and conducted an analysis to identify the most appealing NETPs. We evaluated 36 NETPs configurations considering their technical maturity, economic feasibility, greenhouse gas removal potential, resource use, and environmental impacts. We found multiple trade-offs among these indicators, which suggests that a regionalised portfolio of NETPs exploiting their complementary strengths is the way forward. Although no single NETP is superior to the others in terms of all the indicators simultaneously, we identified 16 Pareto-efficient NETPs. Among them, six are deemed particularly promising: forestation, Soil Carbon Sequestration (SCS), enhanced weathering with olivine and three modalities of Direct Air Carbon Capture and Storage (DACCS). While the co-benefits, lower costs and higher maturity levels of forestation and SCS can propel their rapid deployment, these NETPs require continuous monitoring to reduce unintended side-effects – most notably the release of the stored carbon. Enhanced weathering also shows an overall good performance and substantial co-benefits, but its risks – especially those concerning human health – should be further investigated prior to deployment. DACCS presents significantly fewer side-effects, mainly its substantial energy demand; early investments in this NETP could reduce costs and accelerate its scale-up. Our insights can help guide future research and plan for the sustainable scale-up of NETPs, which we must set into motion within this decade.

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