Study on the influence of crosslinking density and free polysiloxan chain length on oxygen permeability and hydrophilicity of multicomponent silicone hydrogels

To investigate the influence of crosslinking density and free polysiloxane chain length on oxygen permeability and hydrophilicity of multicomponent silicone hydrogels, two kinds of silicone macromonomers, single methacrylate terminated silicone macromonomers (PDMS-1) and double methacrylate terminated silicone macromonomers (PDMS-2), were synthetized, respectively. Then, a series of multicomponent silicone hydrogels with different crosslinking densities and free polysiloxane chain lengths were prepared by copolymerization of obtained silicone macromonomers, silicone monomer tris(trimethylsiloxy)-3-methacryloxpropylsilane (TRIS), and hydrophilic monomers. The oxygen permeability coefficient (Dk), equilibrium water content (EWC), light transmittance, and mechanical properties of silicone hydrogels were characterized. The results indicated that the longer free polysiloxane chain was beneficial to the increase of Dk values and EWC of silicone hydrogels. With the increase of crosslinking density, the Dk values and EWC of the silicone hydrogels decreased. This work provided a new idea for the preparation of high-permeability silicone hydrogels in the future. Graphical abstract