Icephobic, Pt-Cured, Polydimethylsiloxane Nanocomposite Coatings

To explore novel coatings with potential for easy release of ice (icephobicity), a series of platinum-cured silicone coatings was prepared incorporating SYL-OFF 7210, designated MQ-R, as a nanoscale reinforcing component. These optically transparent coatings are designated according to cure temperature and MQ-R wt %, for example, Pt-PDMS(25)-20 for 25 °C cure and 20 wt % MQ-R. Surface characterization included dynamic contact angles and morphology by atomic force microscopy. Bulk characterization was accomplished with stress-strain measurements at 25 °C and dynamic mechanical analysis from -110 to 150 °C. Ice adhesion tests at -10 °C showed modulus had a dominant effect in increasing τ_ice, the peak removal force. At -30 °C, storage modulus was greater for coatings cured at 100 °C compared to 25 °C, but ice removal tests at -30 °C (-22 °F) consistently showed τ_ice for Pt-PDMS(100) MQ-R compositions was less than τ_ice for corresponding Pt-PDMS(25) coatings. This unexpected result was explained by proposing that supercooled water at hydrophilic interfacial sites (-10 °C) does not impede ice removal but frozen water pins ice at -30 °C. Interestingly, MQ-R was found to be a reactive filler that increased modulus after 100 °C cure especially for Pt-PDMS(100)-30 (3 MPa) and Pt-PDMS(100)-40 (5 MPa). In summary, by virtue of resistance to ice adhesion Pt(PDMS) coatings with low MQ-R content have potential for conferring energy savings and safety while high MQ-R content results in noteworthy mechanical properties.