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Materials that show multicolor electrochromism, including yellow and green, are highly applicable for various smart applications including voltage-tunable multicolor electrochromic (EC) displays and camouflage devices. Although metallo-supramolecular polymers (MSPs) show excellent EC color variability with attractive EC properties, the generation of multicolor electrochromism from one MSP is still difficult. Moreover, an MSP-based multicolor EC device (ECD) that also exhibits yellow and green EC colors has not been realized to date. Herein, we report the synthesis of a dual redox-responsive heterobimetallic supramolecular polymer (PolyOsRu) as a multicolor EC material that can also be used for camouflage applications. PolyOsRu was synthesized by stepwise homoleptic complexation of Os 2+ and Ru 2+ ions using a 2,2′:6′,2″-terpyridine-based ligand and characterized by various analytical and spectroscopic techniques. The polymer shows broad absorption (312−671 nm) and well-separated dual redox potentials of Os 2+ /Os 3+ (E 1/2 = 0.59 V) and Ru 2+ /Ru 3+ (E 1/2 = 0.93 V) pairs. A thin film of PolyOsRu on ITO displays reversible multicolor (brown−red ↔ yellow ↔ green) electrochromism with a maximum optical contrast of ∼58%, fast EC color switching (<1 s), a good coloration efficiency of 404.39 cm 2 /C, and a more than 2400 EC cycling stability. Finally, the fabrication of a solid-state ECD and a prototype EC camouflage display with the polymer film is demonstrated to represent its potentiality as a multicolor EC material for display and camouflage applications.

Hydrophobic polyurethane (PU) films are widely used for various commercial and industrial applications due to their excellent water repelling and self-cleaning property. Nevertheless, achieving appreciable hydrophobicity in PU film is quite a challenge. Herein, we report on the development of a novel hydrophobic PU (fluorinated polyurethane [FCO-PU]) film and comprehensively evaluate its anticorrosive property. The FCO-PU was prepared by structural modification of castor oil (CO) through attachment of long fluorocarbon chains as pendant groups onto the backbone of CO. A model PU film (CO-PU) was also prepared from unmodified CO to compare the properties of FCO-PU film. All intermediate compounds, FCO-PU and CO-PU films were characterized by various spectroscopic techniques. Morphological, thermal and mechanical properties of the PU films were analyzed by field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical thermal analysis (DMTA) studies. Successful introduction of long fluorocarbon chains into the FCO-PU film is reflected by its high hydrophobicity with a water contact angle of 119.1 , compared to the model CO-PU film with a water contact angle of 84.4 . Anticorrosive properties of the PU films were evaluated by polarization technique and electrochemical impedance spectroscopy under corrosive environment and the obtained results reveal a significant corrosion resistance (corrosion rate: 6.72 Â 10 À6 mm/year) behavior by the FCO-PU film. This work represents an effective strategy for the backbone modification of CO to develop novel functional PU materials.

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