Synthesis of PBS Two different polyborosiloxanes were synthesised, LPBS using a low molar mass PDMS-OH (Mn = 4.6 kg mol -1 ; Đ = 2.1) and HPBS employing a higher molar mass PDMS-OH (Mn = 40.0 kg mol -1 ; Đ = 2.1). Apart from the different molar mass PDMS-OH precursors, the general synthesis of the two polyborosiloxanes was identical and adapted from the literature. PDMS-OH (20.0 g, 270.3 mmol) was dissolved in toluene (250 mL) in a two-necked round bottom flask attached with a Dean-Stark apparatus, condenser and internal thermometer.