Here CN9021 acrylic ester resin
was chosen as the oligomer. It is a urethane acrylate compound comprising a flexible polyether
diol segment, a relatively flexible aliphatic diisocynate segment in its structure, and a high
molecular weight. The resulting homopolymer of CN9021 has high flexibility, low modulus, and
is moisture resist.[108] DMPA and BP were synergistically used as co-initiators, to achieve
complete bulk and surface curing in thin films.[109] A few reactive diluents were used, including
IDA to reduce the viscosity of the precursor solutions, lower the modulus of the co-polymers,
and increase hydrophobicity. IBOA was used to improve the toughness, and TMPTA to provide
the baseline crosslinking.[107] HDDA was used as the main crosslinker to adjust the mechanical
and electromechanical properties of the material. DBEF was used as a plasticizer.