Graft‐Copolymer‐Based Approach to Clear, Durable, and Anti‐Smudge Polyurethane Coatings

Abstract

Clear anti-smudge coatings with a thickness of up to tens of micrometers have been prepared through a graft-copolymer-based approach from commercial precursors. The coatings repel water, diiodomethane, hexadecane, ink, and an artificial fingerprint liquid. In addition, they can be readily applied onto different substrates using different coating methods. These coatings could find applications in protecting hand-held electronic devices from fingerprints, windows from stains, and buildings from graffiti.

Clear and Durable Epoxy Coatings that Exhibit Dynamic Omniphobicity

“…[21,22] They are called NANOGLIDE coatings because they bore nanoreservoirs of a grafted liquid polymer and omniphobicity-enabling surface chains. The coatings had superior liquid sliding properties even though a low amount of the omniphobic reagent was introduced, because the grafted chains self-enriched themselves on the surfaces.…”

“…[12] A caution against this method is that the resultant coating may not slide oil [13] or shrink ink [14] poly(ethylene imine) (Scheme 1) and g denotes graft. [21] Although PDMS was incompatible with the epoxy formulation mentioned above, PEI was soluble in it. We hypothesized that reacting PEI with DGEBA would produce a polymer that bore many pendant grafted epoxide rings.…”

“…Therefore, the graft copolymer approach would yield a NANOGLIDE epoxy coating ( Figure 1 a). [ 21,22 ] PEI was chosen as the backbone of the graft copolymer because branched PEI was commercially available and PEI readily and quantitatively reacted with PDMS to yield PEIg -PDMS (see Supporting Information). To prepare PEIg -PDMS, an equal mass of PEI and PDMS at the number-average molecular weights ( M n ) of 10 × 10 3 and 5.0 × 10 3 Da, respectively, were reacted at 60 °C for 48 h. The disappearance of PDMS during this process was monitored by size exclusion chromatography and this analysis indicated that PDMS was fully reacted with PEI by 48 h ( Figure S1, Supporting Information).…”

“…However, a monolayer that is applied on the touch screens of a cell phone, for example, is worn off under prolonged rubbing.Our group invented polyurethane NANOGLIDE coatings that overcame all of the afore-mentioned challenges. [ 21,22 ] They are called NANOGLIDE coatings because they bore nano reservoirs of a g rafted li quid polymer an d omniphobicitye nabling surface chains. The coatings had superior liquid sliding properties even though a low amount of the omniphobic reagent was introduced, because the grafted chains self-enriched themselves on the surfaces.…”

“…Additionally, these coatings were wear-resistant because they could be made into any thickness and their surfaces were self-regenerating: upon the rupture of the nano-reservoirs by wearing, chains of the liquid polymer replenished the worn surface again. Our prior research demonstrated that not only poly(perfl uoropropylene oxide) [ 21 ] but also the less expensive PDMS [ 22 ] could be used to render dynamic omniphobicity. We report herein the preparation of dynamically omniphobic epoxy coatings and verify our hypothesis that the matrix of NANOGLIDE coatings could also be changed.For relevance, we rendered in one case omniphobic properties to a commercial epoxy formulation that yields a clear glass-like coat on dining tables.…”