Self-healing Omniphobic POSS-based NP-GLIDE Coating
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Authors
Wan, Zhecheng
Date
2025-08-25
Type
thesis
Language
eng
Keyword
Functional coating , Anti-smudge , Self-healing , Materials chemistry , Surface chemistry , Polymer chemistry
Alternative Title
Abstract
Durable omniphobic coatings are essential for protective optics, biomedical devices, and consumer surfaces, yet most fluoropolymer top-coats lose function once abraded. This thesis presents a nanophase-segregated polyhedral oligomeric silsesquioxane (POSS)–based NP-GLIDE coating that integrates omniphobicity, mechanical robustness, and thermally activated self-healing. The coating family, denoted (SH)x2k(tA)y, is constructed from T8 SH/tA-functional POSS cages bearing ~2 kDa PDMS side chains and cross-linked into a thiourethane/hindered-urea adaptive network using a mixed aliphatic–cycloaliphatic isocyanate pair—hexamethylene diisocyanate trimer (HDIT) and isophorone diisocyanate (IPDI). Formulations (≈ 110 – 150 mg/mL) are prepared by dissolving the cage and crosslinkers separately in butyl acetate/DMF, combining stoichiometrically, casting, and removing solvent in staged evaporations, followed by nitrogen-protected thermal curing at 110 – 120 °C for 8 – 12 h to yield uniform ~40 µm films.
Molecular-level structure and purity are confirmed by 1H/29Si NMR (quantitative vertex integrations) and SEC (narrow dispersities). The cured films exhibit a hierarchical morphology: ATR-IR verifies thiourethane and hindered-urea formation with an intact POSS framework; UV–Vis transmittance of 40 µm coatings exceeds 90% at 550 nm, consistent with PDMS-rich domains (~25 nm) lying below the scattering limit. Nanoindentation (Oliver–Pharr method) shows glass-like hardness and high elastic recovery, while cylindrical mandrel bends demonstrate polymer-like flexibility with 2 mm pass in both inward and outward orientations. Wetting tests show high advancing/receding angles and low roll-off for water and low-γ liquids, and even permanent-marker ink contracts to beads within seconds. Self-healing is evidenced by closure of deliberate mechanical damage (razor/nanoindentation) upon brief annealing; moreover, annealing restores omniphobicity after PDMS-brush depletion (e.g., by plasma), indicating rapid surface reconstruction from subsurface PDMS reservoirs. TGA and DSC establish wide thermal operating windows, and AFM maps nanoscale phase contrast that underpins the coating’s combined hardness and repellency.
Together, these results define a scalable route to transparent, omniphobic, and intrinsically self-healable hybrid films. NP-GLIDE provides a versatile platform for next-generation anti-fouling, anti-icing, and debris-shedding surfaces where maintenance access is limited.