| abstract |
A color-appearing ink composition includes a surfactant blend of at least two non-ionic surfactants having hydrophilic-lipophilic balance values greater than 10, or a non-ionic surfactant having a hydrophilic-lipophilic balance value greater than 10 and a charged surfactant. The composition includes one or more water-insoluble leuco dyes, a developer and a desensitizer. The composition may be applied to a substrate to form a sensor. |