Viscoelastic solid-repellent coatings for extreme water saving and global sanitation

Jing Wang, Lin Wang, Nan Sun, Ross Tierney, Hui Li, Margo Corsetti, Leon Williams, Pak Kin Wong, Tak Sing Wong

Research output: Contribution to journalArticlepeer-review

78 Scopus citations


Water scarcity threatens over half of the world’s population, yet over 141 billion litres of fresh water are used globally each day for toilet flushing. This is nearly six times the daily water consumption of the population in Africa. The toilet water footprint is so large primarily because large volumes of water are necessary for the removal of human faeces; human faeces is viscoelastic and sticky in nature, causing it to adhere to conventional surfaces. Here, we designed and fabricated the liquid-entrenched smooth surface (LESS)—a sprayable non-fouling coating that can reduce cleaning water consumption by ~90% compared with untreated surfaces due to its extreme repellency towards liquids, bacteria and viscoelastic solids. Importantly, LESS-coated surfaces can repel viscoelastic solids with dynamic viscosities spanning over nine orders of magnitude (that is, three orders of magnitude higher than has previously been reported for other repellent materials). With an estimated 1 billion or more toilets and urinals worldwide, incorporating LESS coating into sanitation systems will have significant implications for global sanitation and large-scale wastewater reduction for sustainable water management.

Original languageEnglish (US)
Pages (from-to)1097-1105
Number of pages9
JournalNature Sustainability
Issue number12
StatePublished - Dec 1 2019

All Science Journal Classification (ASJC) codes

  • Global and Planetary Change
  • Food Science
  • Geography, Planning and Development
  • Ecology
  • Renewable Energy, Sustainability and the Environment
  • Urban Studies
  • Nature and Landscape Conservation
  • Management, Monitoring, Policy and Law


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