4 4 hexafluoroisopropylidene diphthalic anhydride 6fda

Butylamine (99 +%), pentylamine (99%), and hexylamine (99%) were purchased from Acros Organics (Morris Plains, NJ, USA). 3,5-dinitrobenzoyl chloride (DNBC) (96.5%), propylamine (98%), tert-Butylamine (99.5%), 4,4′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) (99%), anhydrous N,N-dimethylacetamide (DMAc) (99.8%), triethylamine (TEA) (99.5%), hydrazine monohydrate (80%), anhydrous pyridine (99.8%), and Pd/C (10%) were purchased from Sigma-Aldrich (Milwaukee, WI, USA). All other reagents and solvents were purchased commercially as analytical grade and used without further purification.

Ethylene glycol dimethacrylate (EGDMA), triethylene glycol dimethacrylate (TIEGDMA), tetraethylene glycol dimethacrylate (TTEGDMA), 1,4-butanediol dimethacrylate (BDDMA), tetraethylene glycol diacrylate (TTEGDA) and 1,4-butanediol diacrylate (BDDA) were purchased from Sartomer Co. (Exton, PA, USA)and used without any purification. 4,4′-(Hexafluoroisopropylidene)diphthalic anhydride (6FDA) (98%), 4,4′-(hexafluoroisopropylidene)dianiline (6FpDA) (98%) and 4,4′-(9-fluorenylidene)dianiline (AFL) (98%) were purchased from Sigma-Aldrich (St. Louis, MO, USA) or TCI Chemicals (Zwijndrecht, Belgium) and additionally purified by vacuum sublimation. The photoinitiator 2,2-dimethoxy-2-phenylacetophenone (DMPA) (99%) (Sigma-Aldrich) was used as received. m-Cresol (99%) was distilled under reduced pressure. N-methyl-2-pyrrolidone and methanol were used without any purification.

4,4′-(Hexafluoroisopropylidene)diphthalic anhydride (6FDA), allyl isocyanate, and platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex solution (in xylene) were purchased from Sigma-Aldrich Korea (Seoul, Republic of Korea). Bis(3-aminopropyl)-terminated polydimethylsiloxane (PDMS) ( $\overline{M}$ _n ~3000) and trimethylsiloxy-terminated methylhydrosiloxane-dimethylsiloxane (MHS-PDMS) copolymers (MHS unit mole % = 0.5–1.5) were purchased from Gelest (Morrisville, PA, USA). Tetrahydrofuran (THF) and methanol were purchased from Samchun Chemicals (Seoul, Republic of Korea), distilled from N₂/benzophenone, and stored under nitrogen atmosphere. Pyridine was purchased from Alfa Aesar Chemicals (Ward Hill, MA, USA). Acetic anhydride was purchased from Junsei Chemical Co., Ltd. (Tokyo, Japan). A commercial IGBT module was purchased from I.G. International (Busan, Republic of Korea) and its insulating material was characterized. It is considered that the insulating material is a PDMS-based gel (i.e., silicone gel) because its IR spectrum is practically the same as that of an authentic PDMS (Figure S2).