title: Lamellar, micro-phase separated blends of methyl cellulose and dendritic polyethylene glycol, POSS-PEG.
abstract: Blends of methyl cellulose (MC) and liquid pegylated polyoctahedralsilsesquioxane (POSS-PEG) were prepared from non-gelled, aqueous solutions at room temperature (RT), which was below their gel temperatures (Tm). Lamellar, fibrillated films (pure MC) and increasingly micro-porous morphologies with increasing POSS-PEG content were formed, which had RT moduli between 1 and 5GPa. Evidence of distinct micro-phase separated MC and POSS-PEG domains was indicated by the persistence of the MC and POSS-PEG (at 77K) crystal structures in the X-ray diffraction data, and scanning transmission electron images. Mixing of MC and POSS-PEG in the interface region was indicated by suppression of crystallinity in the POSS-PEG, and increases/decreases in the glass transition temperatures (Tg) of POSS-PEG/MC in the blends compared with the pure components. These interface interactions may serve as cross-link sites between the micro-phase separated domains that permit incorporation of high amounts of POSS-PEG in the blends, prevent macro-phase separation and result in rubbery material properties (at high POSS-PEG content). Above Tg/Tm of POSS-PEG, the moduli of the blends increase with MC content as expected. However, below Tg/Tm of POSS-PEG, the moduli are greater for blends with high POSS-PEG content, suggesting that it behaves like semi-crystalline polyethylene oxide reinforced with silica (SiO1.5).
authors.affiliation: Department of Chemistry, Temple University, Philadelphia, PA 19122, United States.
authors.forename: Parameswara Rao
authors.initials: PR
authors.lastname: Chinnam
authors.affiliation: Department of Chemistry, Temple University, Philadelphia, PA 19122, United States.
authors.forename: Ramya
authors.initials: R
authors.lastname: Mantravadi
authors.affiliation: Department of Chemistry, Temple University, Philadelphia, PA 19122, United States.
authors.forename: Jayvic C
authors.initials: JC
authors.lastname: Jimenez
authors.affiliation: Department of Mechanical Engineering, Temple University, Philadelphia, PA 19122, United States.
authors.forename: Dmitriy A
authors.initials: DA
authors.lastname: Dikin
authors.affiliation: Department of Chemistry, Temple University, Philadelphia, PA 19122, United States. Electronic address: slwunder@temple.edu.
authors.forename: Stephanie L
authors.initials: SL
authors.lastname: Wunder
mesh_terms: D055595:Mechanical Phenomena; D008747:Methylcellulose / Q000737:chemistry*; D017646:Organosilicon Compounds / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D044366:Transition Temperature
chemical_list: D017646:Organosilicon Compounds; D011092:Polyethylene Glycols; D008747:Methylcellulose
keywords: Anti-fouling methylcellulose blends; Methyl cellulose; Micro-phase separation; Microporous methyl cellulose blends; Polyethylene glycol POSS