Blending Method PBS (250 mg mL -1 ) and P3HT (25 mg mL -1 ) were dissolved separately in chlorobenzene at 80 °C under stirring for 3 hrs, before being combined in ratios of PBS:P3HT 900:100, 950:50, 990:10, 995:5 and 999:1 (w/w). The solutions were stirred overnight at 80 °C to ensure full mixing. After the magnetic stirrer bars were removed, they were placed in a vacuum oven at room temperature for 4 hrs, then 70 °C for 2 hrs, then 120 °C overnight to dry to give a dark brown solid. The resulting polyborosiloxane:P3HT blends were stored under vacuum between measurements and then heated to 120 °C under vacuum prior to any measurements to remove any residual moisture.