Unanticipated bright blue fluorescence produced from novel hyperbranched polysiloxanes carrying unconjugated carbon-carbon double bonds and hydroxyl groups

One-pot polycondensation reaction of triethoxyvinylsilane (A-151) with excessive neopentyl glycol (NPG) is employed as an efficient and facile methodology for the synthesis of novel hyperbranched polysiloxanes contemporaneously bearing plenty of unconjugated carbon-carbon double bonds and hydroxyl groups (HPUHs). Interestingly, the obtained HPUHs obviously without containing conventional chromophores exhibit conspicuous ultraviolet absorbency and bright blue photoluminescence when irradiated by a UV lamp with 365 nm wavelength. The excitation and emission intensities of the as-prepared polymers progressively grow along with raising their molecular weights and concentrations, and even the brightest blue glow in the solid state is observed, suggesting the emission intensity is molecular-weight and concentration-dependent. The preliminary investigation indicates that both the carbon-carbon double bond and the hydroxyl group are very important in the formation of blue-luminescent species. Thus, this work opens a new route to design new light-emitting materials.