Cellulose-based hybrid glycosilicones via grafted-to metal-catalyzed hydrosilylation: "When opposites unite".

Hydrosilylation catalyzed by the rhodium(I) complex [Rh(acac)(CO) ₂ ] or platinum(0)-based Karstedt's catalyst was employed to combine hydrophilic propargylated hydroxyethyl cellulose and hydrophobic hydride-terminated polydimethylsiloxane to give polymer hybrid structures. The final polymers were characterized by FTIR, solid state ¹ H, ¹³ C and ²⁹ Si NMR, contact angle, microcalorimetry and thermogravimetry measurements. The grafting degree was controlled by the catalyst choice and by the reagent load variations; an increase of the polysiloxane load and a change from Karstedt's to the rhodium catalyst led to a higher (from 2 to 7%) silicon content in the glycosilicones. The glycosilicones were insoluble in water, but swelled in organic solvents (DMSO, DMF, and chloroform). The hydrophilicity of the glycosilicones decreased with incrementing silicon content: the contact angles increased from 30 (cellulose) to 103-131° in the hybrids. The glycosilicones obtained via the hydrosilylation are less toxic toward algae Chlorella vulgaris and infusoria Paramecium caudatum than those obtained with CuAAC.
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