A few suggested references:

C. Pathmamanoharan, "Synthesis of trimethoxysilyl-terminated poly(12-hydroxy-stearic acid) and the subsequent grafting onto charged silica particles", Colloids Surf., 50, 1990, 1-6.

H. Yuan, H. Ba, Y. Wang, Ch. 12: "Preparation and characterization of stearic acid/SiO2: Nano‐encapsulated phase change materials via sol‐gel method", in: L. Li, D.P. Guillen, N.R. Neelameggham, L. Zhang, Z. Jingxi, L. Xuan, S.N. Basu, N. Haque, T. Wang, D.E. Verhulst, A. Pandey (Eds.), "Energy Technology 2016: Carbon Dioxide Management and Other Technologies", The Minerals, Metals & Materials Society (TMS) / Wiley, 2016, pp. 99-106; DOI: 10.1002/9781119274704.ch12

X. Liu, H. Bai, Y. Wang, K. Zhou, H. Li, “Preparation of silica encapsulated stearic acid as composite phase change material via sol-gel process”, TMS, 2014.

M.S. Chattha, J.C. Cassatta, "A new preparation of nonaqueous dispersions", Ind. Eng. Chem. Prod. Res. Dev., 25(3), 1986, 453–456.

Interesting discussion. Following with intent.

Regards

I think you can graft it by APTS

Carlos Araújo Queiroz thanks a lot for your suggestions

Add silica to ethanol, after sonication add stearic acid, (SiO2: SA, 10:1), followed by heating at 60°C for 1-2 hours.