Silated hydroxypropylmethylcellulose (Si-HPMC) is a modified biopolymer used in biomaterial's domain. A hydroxypropylmethylcellulose (HPMC) was functionalised with silane groups. The macromolecular solution of Si-HPMC (pH 12.9) generates an elastic state at physiological pH (~7.4). In this work we present the gel formation of Si-HPMC resulting from the condensation of silanol groups. The crosslinked hydrogel was characterized using rheological techniques. With the scalar percolation model the gelation time was determined as a function of Si-HPMC concentration at 37 °C.