title: Self-assembly and morphology of gel networks in l,3:2,4-bis-O-(p-methylbenzylidene)-D-sorbitol/n-dibutylphthalate.
abstract: We investigated the self-assembling structure of the 1,3:2,4-bis-O-(p-methylbenzylidene)-D-sorbitol (PDTS)/n-dibutylphthalate (DBP) system in the parameter space of temperature T and solute concentration Phi(PDTS). Optical microscopic studies revealed that the phase diagram can be divided into four regions. In region I at high T the system is a homogeneous solution. In region II at lower T and low Phi(PDTS), the system still has fluidity but has microgels having spherulitic texture of PDTS crystallites. Regions III and IV at even lower T but higher Phi(PDTS) are in a gel state. In region III, the PDTS forms volume-filling spherulites due to the solid-liquid phase transition of the saturated PDTS solutions. In region IV at the lowest T, both the liquid-liquid phase-separation process and the solid-liquid transition of the PDTS are involved in the self-assembling processes. In this region a bicontinuous phase-separated structure is first formed by liquid-liquid phase separation via spinodal decomposition (SD). The subsequent solid-liquid transition of the PDTS in the PDTS-rich region forms percolating crystalline fibrils rather than spherulites. The formation of the crystalline fibrils pins further growth of the bicontinuous structure via SD.
authors.affiliation: Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 606-8501, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Mikihito
authors.initials: M
authors.lastname: Takenaka
authors.forename: Kenji
authors.initials: K
authors.lastname: Saijo
authors.forename: Takeji
authors.initials: T
authors.lastname: Hashimoto
mesh_terms: D003993:Dibutyl Phthalate / Q000737:chemistry*; D005782:Gels / Q000737:chemistry*; D044367:Phase Transition; D010968:Plasticizers / Q000737:chemistry; D013012:Sorbitol / Q000737:chemistry*
chemical_list: D005782:Gels; D010968:Plasticizers; D003993:Dibutyl Phthalate; D013012:Sorbitol