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Daniel J Preston

@danpreston.bsky.social

Assistant professor, director of the PI Lab (https://pi.rice.edu) at Rice University; previously postdoc in Whitesides group at HarvardCCB, PhD at MIT MechE.

130 Posts141 Follower186 Folgt
Daniel J Preston@danpreston.bsky.social · 8mo ago

Glad this work is now published! We unlock new applications in the energy, food, and medical industries where management and repellency of hot liquids has been a longstanding challenge. Story and video: news.rice.edu/news/2026/he... Research paper: pubs.acs.org/doi/10.1021/...

Scalable Hot-Water-Repellent Superhydrophobicity via Thermal Insulation

Superhydrophobic surfaces, which rely on a combination of surface texture and chemistry, often lose their repellent behavior when contacted by hot water (≳40 °C) because the impinging hot water replaces the requisite air layer within the surface texture via evaporation and recondensation. In contrast to previous approaches targeting this condensation-induced failure mode that rely on intricately tailored surface structures or complex chemical treatments, we present a scalable approach based on thermal design: the multilayered insulated superhydrophobic (MISH) coating mitigates condensation-induced failure by preventing heat transfer. Superhydrophobicity is retained at impinging water temperatures up to 90 °C, with durability demonstrated via long-term (>1 million impacts) droplet impingement experiments. We explain the mechanism for this approach with a detailed thermal model; the model reveals that the underlying physical behavior is self-similar across coating parameters and impinging fluid temperatures. The MISH coating accommodates curved geometries and large surfaces, and it is over 4 orders of magnitude less expensive than cleanroom-nanofabricated alternatives, indicating promise for practical use in the energy sector, chemical processing, and the food and medical industries.

pubs.acs.org

Daniel J Preston@danpreston.bsky.social · 2y ago

New work led by Trevor Shimokusu in collaboration with researchers at the The University of Edinburgh and the Wehmeyer lab here at Rice shows mask-enabled topography contrast patterning with implications for phase change heat transfer and thermal rectification: doi.org/10.1021/acs....

Mask-Enabled Topography Contrast on Aluminum Surfaces

Patterned solid surfaces with wettability contrast can enhance liquid transport for applications such as electronics thermal management, self-cleaning, and anti-icing. However, prior work has not explored easy and scalable blade-cut masking to impart topography patterned wettability contrast on aluminum (Al), even though Al surfaces are widely used for thermal applications. Here, we demonstrate mask-enabled topography contrast patterning and quantify the resulting accuracy of the topographic pattern resolution, spatial variations in surface roughness, wettability, drop size distribution during dropwise condensation, and thermal emissivity of patterned Al surfaces. The method uses blade-cut vinyl mask templates and a commercially available lacquer resin that serves as a polymer resist against etching. Programmable mask templates enable complex patterning of wettability and emissivity contrast with feature sizes down to ∼1.5 mm. As-fabricated patterned samples show a water contact angle (θ) contrast from <5° to 80° between etched and smooth zones, while patterned samples that are further coated with a hydrophobic promoter show θ contrast between 150° and 120° on etched and smooth zones, respectively. In addition to measuring this wettability contrast via contact angle goniometry, we use condensation visualization experiments to study the spatially controlled condensate morphologies and drop size distributions. These condensation studies demonstrate enhanced droplet shedding on the superhydrophobic regions of striped patterned surfaces compared to homogeneous superhydrophobic surfaces. Motivated by the role of thermal radiation in many phase change processes, we use infrared thermography to map topography-mediated thermal emissivity (ε) contrast between etched (ε ≈ 0.65) and smooth (ε ≈ 0.26) regions. Thus, our study provides a route for researchers to readily create complex and scalable topography-patterned Al surfaces for potential applications in vapor chamber thermal rectification, radiative cooling condensation heat transfer, and high-temperature Leidenfrost or film boiling processes.

doi.org

Daniel J Preston@danpreston.bsky.social · 2y ago

Great new perspective in Science Robotics out this week! Take a look at this article by @quisebell.bsky.social to learn more, and work toward making positive changes with intentionality.

Marquise Bell@quisebell.bsky.social · 2y ago

How about an academic post? Excited to share my solo-authored work published today in Science Robotics (@science.org). I detailed the importance of intentionality in creating diverse and equitable spaces within robotics, drawing from my own experiences. www.science.org/doi/10.1126/...

Daniel J Preston@danpreston.bsky.social · 2y ago

Great job by @Fayeyap25 defending her PhD thesis in @RiceMECH! Her work applied reaction kinetics to understand virus inactivation, elastomer curing, and manufacturing of soft robots, and she will start her own lab as a faculty member at @uhmanoa in January.

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Daniel J Preston@danpreston.bsky.social · 2y ago

Congrats to our @ricePILab members starting tenure-track faculty positions this year! @ranoop93 at @Tulane, @Zhen_Skyii at @UT_Dallas, and @Fayeyap25 at @uhmanoa - we took a photo in our uni t-shirts before our summer lab social. Looking forward to following their careers!

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Daniel J Preston@danpreston.bsky.social · 2y ago

Congratulations @Zhen_Skyii on successfully defending your PhD thesis in @RiceMECH today! One of the first three members of @ricePILab, Zhen's work has given us a new understanding of the impact of surface contamination, and also how to avoid it.

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