Effect of nature and degree of crosslinking agent of poly(hydroxy-butyl-methacrylate-co-2-ethyl-hexyl-acrylate) networks on the swelling properties in nematic liquid crystal 5cb

A swelling rate study of the poly (hydroxy-butyl-methacrylate-co-2-ethyl-hexyl-acrylate) / 5CB was conducted here to improve the swelling behavior of the physicochemical properties of the copolymer networks in liquid crystals. We experimentally measured the nature and the crosslinking agent concentration effects on the swelling rate. Initial mixtures are composed of monofunctional monomers, hydroxy-butyl-methacrylate (HBMA) and 2-ethyl-hexyl-acrylate (2-EHA), and one of the three bifunctional monomers, poly-propylene-glycol-di-acrylate (PPGDA), tri-propylene-glycol-di-acrylate (TPGDA) or 1,6-hexane-diol-di-acrylate (HDDA) as well as 2-hydroxy-2-methylpropiophenone (Darocur 1173) as a photoinitiator. The copolymers were elaborated by UV irradiation with a reactive formulation. The face-centered central composite design (FC-CCD) of experiments was used to determine the temperature, the crosslinking density and their interactions influence on the swelling behavior of poly (HBMA-co-EHA/crosslinker/Darocur 1173) in the 5CB liquid crystal. The results predicted by this model showed good agreement with experimental values.