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Nitash P Balsara - One of the best experts on this subject based on the ideXlab platform.

  • effect of added salt on disordered poly ethylene oxide block poly methyl methacrylate copolymer electrolytes
    Bulletin of the American Physical Society, 2021
    Co-Authors: Neel Shah, Sajjad Dadashisilab, Michael D Galluzzo, Saheli Chakraborty, Whitney S Loo, Krzysztof Matyjaszewski, Nitash P Balsara
    Abstract:

    We studied the effect of salt addition on a diblock copolymer system with a negative Flory–Huggins Interaction Parameter, χ, indicative of attractive Interactions between the two blocks. The system...

  • Structure and Thermodynamics of Hybrid Organic–Inorganic Diblock Copolymers with Salt
    2019
    Co-Authors: Gurmukh K. Sethi, Nitash P Balsara, Whitney S Loo, Ha Young Jung, Simar Sawhney, Moon Jeong Park, Irune Villaluenga
    Abstract:

    We examine the phase behavior of a hybrid organic–inorganic diblock copolymer/salt mixtures. The experimental system comprises poly­(ethylene oxide)-block-polyhedral oligomeric silsesquioxane (PEO–POSS) mixed with a lithium bis­(trifluoromethane sulfonyl) imide (LiTFSI) salt. Although the diblock copolymers without salt exhibit a classical order-to-disorder transition behavior with increasing temperature, the PEO–POSS/salt mixtures exhibit disorder-to-order transitions with increasing temperature. The analysis of a small-angle X-ray scattering data from the disordered state using Leibler’s random phase approximation enables the determination of an effective Flory–Huggins Interaction Parameter, χeff, for the electrolytes. Unlike conventional systems, χeff increases with increasing temperature. A simple expression is proposed to describe the dependence of χeff on temperature and salt concentration. This enables the calculation of the segregation strength, χeffN, for both ordered and disordered electrolytes. The composition of the electrolytes is quantified by fEO/LiTFSI, the volume fraction of the salt-containing poly­(ethylene oxide)-rich phase. The morphology of electrolytes is presented on a χeffN versus fEO/LiTFSI phase diagram. Over the values of fEO/LiTFSI studied (0.61–0.91), only two ordered phases were found: lamellae and co-existing lamellae/hexagonally packed cylinders

  • measurements of the composition and molecular weight dependence of the flory Huggins Interaction Parameter
    Macromolecules, 2008
    Co-Authors: Alisyn J Nedoma, Megan L Robertson, Nisita S Wanakule, Nitash P Balsara
    Abstract:

    The phase behavior of binary blends of polyolefins is studied using small-angle neutron scattering. Component 1 is polyisobutylene (PIB), and component 2 is deuterated polybutadiene (dPB). Blends o...

  • measurements of the flory Huggins Interaction Parameter using a series of critical binary blends
    Industrial & Engineering Chemistry Research, 2008
    Co-Authors: Alisyn J Nedoma, Megan L Robertson, Nisita S Wanakule, Nitash P Balsara
    Abstract:

    The Flory−Huggins Interaction Parameter, χ, for a series of critical binary blends of polyisobutylene and deuterated polybutadiene was measured by small-angle neutron scattering. χ was determined by fitting the scattering intensity profiles single-phase blends to the well-established random-phase approximation. Our experiments, which covered a wide range of chain lengths, suggest that χ depends on both blend composition and the ratio of the homopolymer chain lengths.

Jin Kon Kim - One of the best experts on this subject based on the ideXlab platform.

  • fabrication of sub 3 nm feature size based on block copolymer self assembly for next generation nanolithography
    Macromolecules, 2017
    Co-Authors: Jongheon Kwak, Kyu Seong Lee, Jaeyong Lee, Avnish Kumar Mishra, Chungryong Choi, Sandip Maiti, Mooseong Kim, Jin Kon Kim
    Abstract:

    For ultrahigh-density storage media and D-RAM, the feature size of lithography should be much reduced (say less than 10 nm). Though some research groups reported feature size of 5–6 nm, further reduced feature size is needed for next-generation lithography. We synthesized, via a reversible addition–fragmentation chain-transfer polymerization, polydihydroxystyrene-block-polystyrene (PDHS-b-PS) copolymers showing lamellar and cylindrical microdomains by adjusting the volume fraction of PS block (fPS). We found that the Flory–Huggins Interaction Parameter (χ) between PDHS and PS was very large, 0.7 at 170 °C. Because of the huge χ, the lamellar domain spacing (L) of PDHS-b-PS with a total molecular weight of 2.1 kg mol–1 and fPS = 0.5 was only 5.9 nm; thus, a sub-3 nm feature size (half-pitch) was successfully obtained. Furthermore, PDHS-b-PS with a molecular weight of 4.2 kg mol–1 and fPS = 0.79 showed hexagonally packed cylinders with 4 nm diameter. We also obtained thin films of PDHS-b-PS with cylindrical...

  • reduction of line edge roughness of polystyrene block poly methyl methacrylate copolymer nanopatterns by introducing hydrogen bonding at the junction point of two block chains
    ACS Applied Materials & Interfaces, 2017
    Co-Authors: Kyu Seong Lee, Jaeyong Lee, Jongheon Kwak, Hong Chul Moon, Jin Kon Kim
    Abstract:

    To apply well-defined block copolymer nanopatterns to next-generation lithography or high-density storage devices, small line edge roughness (LER) of nanopatterns should be realized. Although polystyrene-block-poly(methyl methacrylate) copolymer (PS-b-PMMA) has been widely used to fabricate nanopatterns because of easy perpendicular orientation of the block copolymer nanodomains and effective removal of PMMA block by dry etching, the fabricated nanopatterns show poorer line edge roughness (LER) due to relatively small Flory–Huggins Interaction Parameter (χ) between PS and PMMA chains. Here, we synthesized PS-b-PMMA with urea (U) and N-(4-aminomethyl-benzyl)-4-hydroxymethyl-benzamide (BA) moieties at junction of PS and PMMA chains (PS-U-BA-PMMA) to improve the LER. The U-BA moieties serves as favorable Interaction (hydrogen bonding) sites. The LER of PS line patterns obtained from PS-U-BA-PMMA was reduced ∼25% compared with that obtained from neat PS-b-PMMA without BA and U moieties. This is attributed to ...

Henrich Frielinghaus - One of the best experts on this subject based on the ideXlab platform.

Isabel M Felisberti - One of the best experts on this subject based on the ideXlab platform.

  • flory Huggins Interaction Parameter of poly ethylene oxide poly epichlorohydrin and poly ethylene oxide poly epichlorohydrin co ethylene oxide blends
    Polymer, 1998
    Co-Authors: Marcia Alessandra Cavalaro Pereira Da Silva, Marcoa De Paoli, Isabel M Felisberti
    Abstract:

    Abstract Blends of poly(ethylene) oxide with poly(epichlorohydrin) and poly(epichlorohydrin- co -ethylene oxide) havebeen prepared by the freeze-drying method from benzene solutions of the polymer mixture at different compositions. The miscibility of the mixtures was studied by DSC. A single glass transition temperature is observed for all the blends studied. Measurement of the melting temperature ( T m ) depression for the blends allowed determination of the Flory-Huggins Interaction Parameter (χ 12 ) of the two polymers in the melt using the Nishi-Wang equation. The Hoffman-Weeks extrapolation was applied to obtain equilibrium T m data. The values of the χ 12 obtained from T m depression data were negative for all blends. This suggests the miscibility of the components of the blends.

Seung Soon Jang - One of the best experts on this subject based on the ideXlab platform.

  • molecular modeling approach to determine the flory Huggins Interaction Parameter for polymer miscibility analysis
    ChemPhysChem, 2018
    Co-Authors: Connor P Callaway, Kayla Hendrickson, Nicholas Bond, Seung Min Lee, Parveen Sood, Seung Soon Jang
    Abstract:

    In this work, we present a thorough procedure for estimating the Flory-Huggins χ-Parameter for use in atomistic and mesoscale molecular simulations in computational materials science. In particular, we propose improvements upon traditional Flory-Huggins theory by implementing a Connolly volume normalization (CVN). We apply this technique to several test systems, including a blend of poly (epichlorohydrin) and poly (methyl acrylate), a blend of polyethylene glycol and poly (methyl methacrylate), a blend of polystyrene and deuterated polystyrene, and three molecular-weight variants (monomer, dimer, and trimer) of a triblock copolymer for use in multicompartment micelle applications. Our results demonstrate that the newly developed procedure offers high accuracy and efficiency in predicting the Flory-Huggins χ-Parameter for miscibility analysis compared to traditional experimental and computational methods. There are still several factors that cause the magnitude of the χ-Parameter to vary between simulations performed on molecular species with the same identity but different degrees of polymerization; although we discuss possible explanations for these factors, this is nonetheless a primary focus for further exploration into this new methodology.