Low adherence coating

The invention relates to a coating having a low adherence towards different types of contaminants. Such a coating comprises a crosslinked polymeric network provided with an end-functionalized dangling chain, as a result of which the surface maintains its low surface energy

Self-replenishing low-adherence coatings

Low-adherence coatings are widely used today since their water/oil repellency makes them easily cleanable (a well-known example is PTFE). The low surface tension is provided by fluorine- or silicon-containing species that are present at the film surface. Low adherence coatings have already been developed via surface segregation of fluorinated species. However, it has been shown that the fluorine-enriched layer is very thin, and the coating may not sustain low adherence upon mechanical abrasion. An approach to develop self-replenishing low surface energy coatings is to distribute long perfluoroalkyl-end-capped chains relatively homogeneously in a coating network. In case of surface damage that leads to the loss of the top layers of the coating, fluorinated tails from sub-layers will be able to reorient themselves to minimize the air/film interfacial energy. In order to study the self-replenishing behavior, model polyester precursors with controlled functionality were synthesized via controlled ring-opening polymerization of e-caprolactone using perfluoroalkyl alcohol or polyol as initiators. The as-prepared precursors were cured with polyisocyanate crosslinker to obtain films with low surface energy. The fluorine depth profile and the self-replenishing behavior have been investigated. The influence of the mobility of polymer spacer and network, as well as temperature, on the self-replenishing behavior will be discussed

Low adherence coating containing polymers with low surface energy

A low adherence coating comprises: (a) a crosslinked polymeric network (N), based on a first polymer (P), (b) a low-surface-energy group (E), coupled to the network via (c) a polymeric spacer (S), having the following relationship between the native surface energies of P, E, and S (resp. sp, se, and ss,, in mN/m): se <ss <sp. The coatings have a low adherence towards different types of contaminants. A coating contained a polycaprolactone terminated with perfluorooctyl ethanol. [on SciFinder (R)

Hydrophobic, self-replenishing coatings for polar substrates

Abstract only

Surface characteristics of phenolic resin coatings

Phenolic resins are commonly used as polymer binders for metal, paper and mineral wool substrates. For such applications, mechanical, adhesive and thermal properties are considered most important, and the effect of synthesis and structural parameters on such end-use characteristics are well-documented. However, surface characteristics of cured phenolic resins can be equally relevant and are often overlooked. Widely used resins are phenol-urea-formaldehyde (PUF) and phenol-formaldehyde (PF). It is believed that the inherent chemistry and curing procedure of these resins result in coatings with distinct surface properties and wettability. To gain more insight into surface characteristics such as morphology, chemical composition and wettability of cured PUF and PF resins, different binder formulations were applied on glass substrates and subsequently characterised by Scanning Electron Microscopy (SEM), Contact Angle Goniometry (CAG) and X-Ray Photoelectron Spectroscopy (XPS). The effect of catalyst, chemical composition and curing conditions on surface characteristics of various PUF and PF coatings were investigated. The curing temperature was found to have a strong influence on surface properties; curing at 200 °C yields a surface with varying degrees of oxidation, differences in linkages between phenolic and urea species, and a lower overall nitrogen content in case of urea-containing coatings, resulting in stronger fluctuations in water-wettability compared to surfaces hardened at lower temperatures.</p

Absorption of water and corrosion performance of a clear and pigmented epoxy coating on Al-2024 alloy

The corrosion performance of Al-2024 substrates coated with an epoxy clear coating and a pigmented epoxy coating was investigated. The absorption of water in the pigmented coating was high compared to the clear coating. The clear coating provided a good barrier which is stable beyond 120 days of immersion in a 0.5 M NaCl solution. The shape of the Nyquist plot of the pigmented coating changed with immersion time and reveals the existence of physico-chemical processes in the coating and/or at the interface. Its impedance magnitude at low frequencies remained very high (~ 109 .cm2) after 72 days of immersion in sodium chloride solution. Both coatings exhibited good dry adhesion on Al-2024. The wet adhesion of the clear coating was poor while the stress (~ 9 MPa) required in a pull off adhesion test of the wet pigmented coating remained high

UV-cured self-replenishing hydrophobic polymer films

Self-healing functional polymer surfaces, designed with an intrinsic and spontaneous mechanism which replenishes the damaged surfaces with the original chemical functionalities, are of great interest to maintain a high performance of the functionality and extend the life-time of materials. We report self-replenishing UV-cured hydrophobic polymer films prepared through the incorporation of methacrylate-terminated perfluorinated-dangling chains into poly(ethylene glycol diacrylate) (PEGDA)-based networks. The films are able to spontaneously and fully self-replenish the surface hydrophobicity, multiple times, upon consecutive intentional damages. The rate of recovery was found to be dependent on the glass transition temperature (Tg) of the networks, which directly correlates to the PEG block length in the PEGDA oligomer used. This study demonstrates that an intrinsic self-replenishing mechanism can be implemented in new network architectures, created rapidly and efficiently by free radical UV-polymerization, which allows preparing self-healing functional polymer films in a faster and eco-friendlier way