Paper-based electrospray emitters

This technical note documents the use of paper as electrospray emitters. The porous structure of the paper automatically delivers the liquid by capillary effects without the need of a mechanical pump. The liquid flow rate can be approximately quantified using Washburn equation. Despite the limited durability, paper-based electrospray emitters exhibit unique features such as ease of multiplexing, self-regulated liquid supply without need of pumps, ultra-low cost, and versatility provided through origami.