Selective dye adsorption and metal ion detection using multifunctional silsesquioxane-based tetraphenylethene-linked nanoporous polymers

Abstract

Multifunctional hybrid fluorescent porous materials have been prepared by the Friedel–Crafts reaction of octavinylsilsesquioxane (OVS) with tetraphenylethene (TPE). These hybrid porous polymers possess high surface areas of up to 1910 cm² g⁻¹, and bimodal pore structures with micropores centered at ≈1.4 nm and mesopores centered at ≈4.5 nm. They show a moderate CO₂ adsorption capacity of 6.25 wt% (1.42 mmol g⁻¹) at 273 K/101 kPa. Remarkably, they exhibit highly size-selective adsorption of dye of 1666 mg g⁻¹ for rhodamine B (RB), 1040 mg g⁻¹ for congo red (CR) and 862 mg g⁻¹ for crystal violet (CV). Furthermore, the incorporation of a tetraphenylethene unit induces higher fluorescence (λ_em = 490 nm) and high sensitivity for Fe³⁺, Cu²⁺ and Ru³⁺, especially for Fe³⁺ with K_SV = 140 K M⁻¹. They are very promising for multiple applications in dye separation, sensors, etc.