“Smart coatings are coming and will open the way to more dynamic, higher performing products.” This, according to Anthony Schiavo, an associate at Lux Research and lead author of the report titled, “Surfaces Get Smarter: Scouting Emerging Coatings, Markets and Functionalities.” While today’s coatings provide protection, new technology makes them smart, that is, able to change in response to their environment.

The report evaluates, inter alia, three developing areas. The first is hydrophobic/oleophobic coatings. This is also the subject of Bob Roman’s “Finishing Line” column in this issue (page 90). The column discusses Nissan’s “self-cleaning paint” and related products, and considers the question whether the “self-cleaning car” will make car washing obsolete.

Second, Lux Research discusses liquid-infused coatings, a technology that is entirely new to me, but one version of which was in fact developed as far back as 2009 by two MIT scientists. The duo’s product, called LiquiGlide, acts as a slippery barrier between a surface and a viscous liquid. While this sounds similar to the workings of a hydrophobic surface, the effect is much improved, since LiquiGlide contains none of the microscopic gaps that even superhydrophobic coatings do.

Although potential applications for this product seem plentiful —also in the automotive industry — for now, the developers are focused on consumer-goods packaging. Applied inside a ketchup bottle, for example, the coating clings permanently to its sides, allowing the ketchup to glide off completely, with no residue. If I understand a post at https://newsoffice.mit.edu correctly, however, the product’s formulation has to be customized for every situation. Liquid components of the coating, the blog states, must be compatible with the chemical and physical properties of the sticky product.

SLIPS, a competitor technology to LiquiGlide, is not burdened with the same impediment. The SLIPS liquid-infused coating technology was developed by the Wyss Institute for Biologically Inspired Engineering at Harvard University and is billed at the institute’s website as “a slippery surface that can repel almost anything” — an omniphobic. Wyss claims its technology “combines a lubricated film on a porous solid to create low-cost surfaces that exhibit ultra-liquid repellency, self healing, optical transparency, pressure stability, and self cleaning.” Even insects, Wyss says, will simply slip off protected structures.

The third development Lux Research considers is self-healing coatings. Its report acknowledges that this coatings category has experienced slow growth, and remains “sluggish.”
It finds, though, that the technology has a
future. Not much has happened in the 10 years since Nissan first introduced “Scratch Guard” paint containing a highly elastic resin that repaired scratches.

Some four years later, at the University of Southern Mississippi, a self-healing coating was developed containing chitosan that is derived from crustaceans (lobster, crab, shrimp, etc.). The chitosan is incorporated with traditional polymers and responds to sunlight to fill the scratch. One reported drawback is that it works only once. If your car gets scratched a second time in the exact same spot, you’re out of luck.

It has been several years since we first were introduced to the notion of a car sporting a lotus-effect paint job. Now, to quote from Bob’s previously mentioned column: “Nissan’s self-cleaning Leaf vehicle is on the streets.” How soon, if ever, liquid-infused coatings will find application in automobile finishes is an open question. How fast self-healing coatings will be adopted in future is equally uncertain. What we can be certain of is that automobile paint finishes will continue to evolve and that car washers and detailers alike will have to adapt accordingly.