Synthesis and properties of polyelectrolyte multilayered microcapsules reinforced smart coatings

Abstract

The present research work focuses on the synthesis, characterization and properties of novel polyelectrolyte multilayered microcapsules used as smart additives in organic coatings for corrosion protection of steel parts. Urea formaldehyde microcapsules encapsulated with linalyl acetate (UFMCs), sensitive to mechanical stimulus, were synthesized by in situ emulsion polymerization technique. In the next step, dodecylamine, working as a pH stimulus corrosion inhibitor, was loaded into layers of polyelectrolyte molecules, polyethylenimine (PEI) and sulfonated polyether ether ketone (SPEEK). These were applied layer-by-layer over the microcapsules to form inhibitor containing multilayered urea formaldehyde microcapsules (MLUFMCs). In the next step, MLUFMCs (5.0 wt%) and UFMCs (5.0 wt%) were thoroughly dispersed into the epoxy resin and coated on cleaned steel. A comparison of the structural, thermal and anticorrosive properties indicates that coatings modified with multilayered capsules (PMLSCs) demonstrate good thermal stability, improved self-healing characteristics and higher corrosion resistance compared to the coating modified with urea formaldehyde microcapsules. The improved properties of PMLSCs can be attributed to efficient release of the encapsulated self-healing agent and corrosion inhibitor from the MLUFMCs. Therefore, epoxy coatings modified with the novel multilayered capsules may be attractive for corrosion protection of steel parts used in oil and gas and related industries.

Self-Healing Performance of Multifunctional Polymeric Smart Coatings

“…A typical XRD pattern of the epoxy coating is attained by incorporation of HNTs loaded with NaNO 3 and UFMCs encapsulated with linseed oil into the epoxy matrix to form nanocomposite coatings as shown in Figure 4c. XRD spectrum of the encapsulated UFMCs (inset) is also included in the figure showing the amorphous behavior of the microcapsules and the diffraction peak at 17.5° accounting for the urea formaldehyde as a shell material encapsulating linseed oil as reported in the literature [28].…”

“…Various nanocontainers have been introduced including polymer containers [25], halloysite [26], ion exchange organic resins [27], nanocontainer with a polyelectrolyte shell [28], layered double hydroxide (LDH) conductive polymer matrix [29], montmorillonite [30], and mesoporous inorganic materials [31]. Haddadi et al [32] successfully synthesized a carbon hollow sphere using the silica templating method and encapsulated 2-mercaptobenzimidazole (MBI) inhibitor.…”

Preparation of Polyurethane Monolithic Resins and Modification with a Condensed Tannin-Yielding Self-Healing Property

“…To demonstrate this process, videos (Figure S1) were recorded of both artificial-defected surfaces during the contact with deionized water for 4 h and it is clear that the defect remained almost unchanged for PU, while for the modified PU, the defect began to close by the movement of the coating walls limited by the defect until completely closing the defect after some immersion time. Other works have also studied the self-healing effect by microscopic images [59,69,70,71].…”

Recently Emerging Nanotechnological Advancements in Polymer Nanocomposite Coatings for Anti-corrosion, Anti-fouling and Self-healing

“…Hence, these leaves demonstrate high super-hydrophobicity. Various techniques such as chemical deposition [65] , casting, and chemical etching [66] , sol-gel procedure [67] , photo-lithography [68] , plasma modification [69] , templating [70] , and chemical vapor deposition (CVD) [71] , have undergone utilization in fabricating super-hydrophobic surfaces. Numerous investigations have demonstrated application of polymeric matrices, and PNCs in fabricating hydrophobic/superhydrophobic surfaces [72] , [73] , [74] , [75] .…”