Blended poly (ether sulfone) and poly (ethylene naphthalate) as a scintillation material

• A blended substrate of PES and PEN is characterised as a scintillation material.
• The excitation and emission maxima are 370 nm and 420 nm, respectively.
• Excitation energy is transferred to a lower energy level prior to emission.
• Based on its emission spectrum, the effective refractive index is 1.70.
• The light yield is 2.23 that of PES and 0.68 times that of PEN.

The advantages of blending two aromatic ring polymers for use as a scintillation substrate for radiation detection have attracted considerable attention. Here, we have characterised the blending of poly (ether sulfone) (PES) and poly (ethylene naphthalate) (PEN), which have dissimilar repeat units. The blended substrate is a faint-amber-coloured resin, and its density is between that of PES and PEN (1.34 g/cm3). Its excitation spectrum has a maximum at 370 nm and differs from the component substrates. However, the emission spectrum is similar to that for PEN substrates, and does not exhibit short-wavelength light from the PES component, even when excited by the excitation maximum of PES. These results reveal that excitation energy is being transferred to a lower energy level before it is emitted as light, with a maximum at 420 nm. By taking into account its emission spectrum, an effective refractive index was determined to be 1.70. Light yield distributions generated by 137Cs and 207Bi radioactive sources indicated that the blended substrate had a yield 2.23 times that of PES, and 0.68 times that of PEN. Overall, the results demonstrate that polymer blends can have scintillation characteristics that differ in some ways from those of the base substrates, with a potential advantage in being able to control them.