Complex fluids under shear: Block copolymers

Nanorheology of Polymers, Block Copolymers, and Complex Fluids

MRS Proceedings ◽

10.1557/proc-366-113 ◽

1994 ◽

Vol 366 ◽

Author(s):

A. Levent Demirel ◽

Lenore Cai ◽

Ali Dhinojwala ◽

Steve Granick ◽

J. M. Drake

Keyword(s):

Block Copolymers ◽

Linear Response ◽

Nonlinear Response ◽

Fourier Transforms ◽

Complex Fluids ◽

Wall Slip ◽

Sliding Velocity ◽

Nonpolar Fluids ◽

Induced Changes ◽

Previous Identification

ABSTRACTThe shear rheology of molecularly-thin films of fluids has been studied experimentally as it depends on sinusoidal frequency (linear response) or on sliding velocity (nonlinear response). Building upon previous identification of a solidlike state that is induced by confinement, we find the shearinduced transition to a sliding state in which the viscous dissipation is essentially velocity-independent. The mechanism appears to involve wall slip but Fourier transforms of the response reveal fluctuations, intrinsic to the sliding state, over all accessible frequencies. Other ongoing studies involve shear-induced changes in the fluorescence of confined fluorescent probes, shear dilatancy, and the contrast between the shear of simple nonpolar fluids, and block copolymers.

Download Full-text

Scattering Methods in Complex Fluids

10.1017/cbo9781139034241 ◽

2015 ◽

Cited By ~ 5

Author(s):

Sow-Hsin Chen ◽

Piero Tartaglia

Keyword(s):

Complex Fluids

Download Full-text

Self-Assembly of Hydrogels From Elastin-Mimetic Block Copolymers

MRS Proceedings ◽

10.1557/proc-724-n8.1 ◽

2002 ◽

Vol 724 ◽

Author(s):

Elizabeth R. Wright ◽

R. Andrew McMillan ◽

Alan Cooper ◽

Robert P. Apkarian ◽

Vincent P. Conticello

Keyword(s):

Block Copolymers ◽

Self Assembly ◽

Triblock Copolymers ◽

Variable Temperature ◽

Inverse Temperature ◽

Temperature Transition ◽

Scanning Calorimetry ◽

Design Synthesis ◽

Inverse Temperature Transition ◽

Functional Biomaterials

AbstractTriblock copolymers have traditionally been synthesized with conventional organic components. However, triblock copolymers could be synthesized by the incorporation of two incompatible protein-based polymers. The polypeptides would differ in their hydrophobicity and confer unique physiochemical properties to the resultant materials. One protein-based polymer, based on a sequence of native elastin, that has been utilized in the synthesis of biomaterials is poly (Valine-Proline-Glycine-ValineGlycine) or poly(VPGVG) [1]. This polypeptide has been shown to have an inverse temperature transition that can be adjusted by non-conservative amino acid substitutions in the fourth position [2]. By combining polypeptide blocks with different inverse temperature transition values due to hydrophobicity differences, we expect to produce amphiphilic polypeptides capable of self-assembly into hydrogels. Our research examines the design, synthesis and characterization of elastin-mimetic block copolymers as functional biomaterials. The methods that are used for the characterization include variable temperature 1D and 2D High-Resolution-NMR, cryo-High Resolutions Scanning Electron Microscopy and Differential Scanning Calorimetry.

Download Full-text

Use of Nonionic Block Copolymers in Vaccines and Therapeutics

Critical Reviews in Therapeutic Drug Carrier Systems ◽

10.1615/critrevtherdrugcarriersyst.v15.i2.10 ◽

1998 ◽

Vol 15 (2) ◽

pp. 89-142 ◽

Cited By ~ 30

Author(s):

Mark J. Newman ◽

Jeffrey K. Actor ◽

Mannersamy Balusubramanian ◽

Chinnaswamy Jagannath

Keyword(s):

Block Copolymers

Download Full-text

Mechanical and Structural Consequences of Associative Dynamic Cross-Linking in Acrylic Diblock Copolymers

10.26434/chemrxiv.10000232.v1 ◽

2019 ◽

Author(s):

Jacob Ishibashi ◽

Yan Fang ◽

Julia Kalow

Keyword(s):

Block Copolymers ◽

Rheological Properties ◽

Diblock Copolymers ◽

Cross Linking ◽

Statistical Copolymer

<p>Block copolymers are used to construct covalent adaptable networks that employ associative exchange chemistry (vitrimers). The resulting vitrimers display markedly different nanostructural, thermal and rheological properties relative to those of their statistical copolymer-derived counterparts. This study demonstrates that prepolymer sequence is a versatile strategy to modify the properties of vitrimers.</p>

Download Full-text