물질 재료의 표면과 바이러스 간의 상관관계

dongascience.donga.com/news/view/46341

물체에 묻은 코로나19 바이러스 생존시간, 표면구조가 결정한다

지금까지 연구에 따르면 코로나19 바이러스는 유리에서는 최대 4일, 플라스틱과 스테인리스 스틸에서는 최대 7일까지 생존하지만 천에서는 2일, 종이에서는 3시간을 버틴다.

 

표면의 돌기 구조에 따라서도 그 생존시간에 영향을 준다는 것이 최근 연구 결과를 통해 밝혀졌는데,

 

 “코로나19 바이러스는 종이, 옷 같은 다공성 표면보다 유리, 플라스틱 같은 불투과성 표면에서 더 오래 생존한다”며 “표면 구조에 따라 침방울의 박막이 버티는 시간이 달라지는 만큼 향후 항바이러스 소재 개발에 활용할 수 있을 것”이라고 말했다. 

 

aip.scitation.org/doi/full/10.1063/5.0037924

 

Why coronavirus survives longer on impermeable than porous surfaces

ABSTRACT

Previous studies reported that the drying time of a respiratory droplet on an impermeable surface along with a residual film left on it is correlated with the coronavirus survival time. Notably, earlier virus titer measurements revealed that the survival time is surprisingly less on porous surfaces such as paper and cloth than that on impermeable surfaces. Previous studies could not capture this distinct aspect of the porous media. We demonstrate how the mass loss of a respiratory droplet and the evaporation mechanism of a thin liquid film is modified for the porous media, which leads to a faster decay of the coronavirus on such media. While diffusion-limited evaporation governs the mass loss from the bulk droplet for the impermeable surface, a much faster capillary imbibition process dominates the mass loss for the porous material. After the bulk droplet vanishes, a thin liquid film remaining on the exposed solid area serves as a medium for the virus survival. However, the thin film evaporates much faster on porous surfaces than on impermeable surfaces. The aforesaid faster film evaporation is attributed to droplet spreading due to the capillary action between the contact line and fibers present on the porous surface and the modified effective wetted area due to the voids of porous materials, which leads to an enhanced disjoining pressure within the film, thereby accelerating the film evaporation. Therefore, the porous materials are less susceptible to virus survival. The findings have been compared with the previous virus titer measurements.

 

 

 

aip.scitation.org/doi/10.1063/5.0049404

Designing antiviral surfaces to suppress the spread of COVID-19

Surface engineering is an emerging technology to design antiviral surfaces, especially in the wake of COVID-19 pandemic. However, there is yet no general understanding of the rules and optimized conditions governing the virucidal properties of engineered surfaces. The understanding is crucial for designing antiviral surfaces. Previous studies reported that the drying time of a residual thin-film after the evaporation of a bulk respiratory droplet on a smooth surface correlates with the coronavirus survival time. Recently, we [Chatterjee et al., Phys. Fluids. 33, 021701 (2021)] showed that the evaporation is much faster on porous than impermeable surfaces, making the porous surfaces lesser susceptible to virus survival. The faster evaporation on porous surfaces was attributed to an enhanced disjoining pressure within the thin-film due the presence of horizontally oriented fibers and void spaces. Motivated by this, we explore herein the disjoining pressure-driven thin-film evaporation mechanism and thereby the virucidal properties of engineered surfaces with varied wettability and texture. A generic model is developed which agrees qualitatively well with the previous virus titer measurements on nanostructured surfaces. Thereafter, we design model surfaces and report the optimized conditions for roughness and wettability to achieve the most prominent virucidal effect. We have deciphered that the optimized thin-film lifetime can be gained by tailoring wettability and roughness, irrespective of the nature of texture geometry. The present study expands the applicability of the process and demonstrates ways to design antiviral surfaces, thereby aiding to mitigate the spread of COVID-19