Liao, Tao; Zhao, Xintong; Yang, Xiao; Coates, Phil; Whiteside, Ben; Jiang, Zhiyong; Men, Yongfeng
Structural evolution of flow-oriented high density polyethylene upon heating: In situ SAXS and WAXD studies
The structural evolution of micro-injection molded high density polyethylene (HDPE) at the molecular and lamellar levels was investigated as a function of temperature during heating process using wide angle X-ray diffraction (WAXD) and small angle X-ray scattering (SAXS) techniques. The molded sample exhibits a peculiar multilayer structure of skin and…
Power Law Relaxations in Lamellae Forming Brush Block Copolymers with Asymmetric Molecular Shape
Yavitt, Benjamin M.; Fei, Hua-Feng; Kopanati, Gayathri N.; Winter, H. Henning; Watkins, James J.
We report the linear viscoelasticity of densely grafted poly(styrene)-block-poly(ethylene oxide) (PS-b-PEO) diblock bottlebrush block copolymers (dbBB) of equal mass fraction over a wide range of backbone degree of polymerization (Nbb = 21119). The difference in side chain length (PS Mn = 2.9 kg/mol, PEO Mn = 5 kg/mol) produces an…
Effect of side chain and backbone length on lamellar spacing in polystyrene-block-poly(dimethyl siloxane) brush block copolymers
Fei, Huafeng; Yavitt, Benjamin M.; Kopanati, Gayathri; Watkins, James J.
We report the synthesis of polystyrene-block-poly(dimethyl siloxane) (PS-b-PDMS) brush block copolymers (BBCPs) through sequential ROMP of norbornene-modified macromonomers (-NB) and explore the effect of side chain length (Nsc) and total backbone degree of polymerization (Nbb) on the self-assembly of lamellar morphologies. Group I (PS-NB Mn = 2.9 kg/mol, PDMS-NB Mn…
Cellular uptake of self-assembled phytantriol-based hexosomes is independent of major endocytic machineries
Rodrigues, Letícia; Schneider, Fabian; Zhang, Xiaohan; Larsson, Elin; Moodie, Lindon W. K.; Dietz, Hendrik; Papadakis, Christine M.; Winter, Gerhard; Lundmark, Richard; Hubert, Madlen
Despite increasing interests in non-lamellar liquid crystalline dispersions, such as hexosomes, for drug delivery, little is known about their interactions with cells and mechanism of cell entry. Here we examine the cellular uptake of hexosomes based on phytantriol and mannide monooleate by HeLa cells using live cell microscopy in comparison…
Self-Assembly of the Bio-Surfactant Aescin in Solution: A Small-Angle X-ray Scattering and Fluorescence Study
Dargel, Carina; Geisler, Ramsia; Hannappel, Yvonne; Kemker, Isabell; Sewald, Norbert; Hellweg, Thomas
This work investigates the temperature-dependent micelle formation as well as the micellar structure of the saponin aescin. The critical micelle concentration ( cmc ) of aescin is determined from the concentration-dependent autofluorescence (AF) of aescin. Values between cmcaescin,AF (10°C) = 0.38 ± 0.09 mM and cmcaescin,AF (50°C) = 0.32 ±…
Ordered structure effects on β-nucleated isotactic polypropylene/graphene oxide composites with different thermal histories
Yu, Yansong; Xu, Ruizhang; Chen, Jinyao; Kang, Jian; Xiang, Ming; Li, Yuanjie; Li, Lu; Sheng, Xingyue
In this paper, the influence of ordered structure effects (OSE) on crystallization behaviors of b-nucleated isotactic polypropylene/graphene oxide (b-iPP/GO) composites with different thermal histories, which crystallized at a slow cooling rate (called SLOW), fast cooling rate (called FAST) and medium cooling rate (called MED), respectively, was studied by differential scanning…
Hierarchical Sticker and Sticky Chain Dynamics in Self-Healing Butyl Rubber Ionomers
Mordvinkin, Anton; Suckow, Marcus; Böhme, Frank; Colby, Ralph H.; Creton, Costantino; Saalwächter, Kay
We present a detailed comparison of the microscopic dynamics and the macroscopic mechanical behavior of novel butyl rubber ionomers with tunable dynamics of sparse sticky imidazole-based sidegroups that form clusters of about 20 units separated by essentially unperturbed chains. This material platform shows promise for application as self-healing elastomers. Size…
Core-crystalline nanoribbons of controlled length via diffusion-limited colloid aggregation
Schmarsow, Ruth N.; Ceolín, Marcelo; Zucchi, Ileana A.; Schroeder, Walter F.
It has been previously reported that poly(ethylene) (PE)-based block copolymers self-assemble in certain thermosetting matrices to form a dispersion of one-dimensional (1D) nanoribbons. Such materials exhibit exceptional properties that originate from the high aspect ratio of the elongated nano-objects. However, the ability to prepare 1D assemblies with well-controlled dimensions is…
Isothermal and non-isothermal cold crystallization of tetrabenzofluorene (TBF) molecules
Boopathi, A. A.; Sampath, Srinivasan; Narasimhaswamy, T.
Design and synthesis of tetrabenzofluorene (TBF) derivatives are carried out to investigate the isothermal and non-isothermal cold crystallization (CC) behavior by various spectroscopic and analytical techniques. The unprecedented CC exhibited by TBF molecules is examined by systematic modification of alkyl chain length (C8–C18 even carbons) on both sides of the…
Topochemical polymerization of hierarchically ordered diacetylene monomers within the block copolymer domains
Krishnan, Deepthi; B, Amal Raj R.; Gowd, E. Bhoje
Integration of polymerizable small molecules within block copolymer based supramolecules provides a new strategy to generate functional materials. Herein we report hydrogen-bonding complexes of photopolymerizable 10,12-pentacosadyionic acid (PCDA) and polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP). We systematically investigate how annealing conditions affect the hierarchical ordering and…