Julia Ann Kornfield

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Artificial protein hydrogels made from a triblock protein (designated AC 10 A, where A is an acidic zipper domain and C 10 comprises 10 repeats of the nonapeptide sequence exhibit normalized plateau storage moduli (G9 ' /nkT) less than 0.13 at all concentrations, pH values, and ionic strengths examined. These gels are surprisingly soft due to loop formation(More)
Perdeuterated 4'-pentyl-4-cyanobiphenyl ͑D5CB͒ was synthesized and its physical properties evaluated and compared to those of 5CB. D5CB retains physical properties similar to those of 5CB, such as phase transition temperatures, dielectric constants, and refractive indices. An outstanding feature of D5CB is that it exhibits a much cleaner and reduced(More)
Efficient, one-pot preparation of synthetically challenging, high molecular weight (MW), narrowly dispersed brush block copolymers and random copolymers in high conversions was achieved by ring-opening metathesis (co)polymerization (ROMP) of various macromonomers (MMs) using the highly active, fast-initiating ruthenium olefin metathesis catalyst(More)
An instrument to study the effects of shearing on the crystallization process in semicrystalline polymers is described. It can impose transient stresses similar to those encountered in polymer processing and provides in situ monitoring of microstructure development during and after cessation of flow. Box-like wall shear stress profiles ͑rise and fall times(More)
In the rich and long-standing literature on the flow-induced formation of oriented precursors to polymer crystallization, it is often asserted that the longest, most extended chains are the dominant molecular species in the "shish" of the "shish-kebab" formation. We performed a critical examination of this widely held view, using deuterium labeling to(More)
PURPOSE To measure the tissue mechanical response to elevated intraocular pressure (IOP) using intact globe expansion of rabbit eyes. This method examined rabbit kit (2-3 weeks old) eyes as a model for weakened tissue and evaluated riboflavin/UVA and glyceraldehyde cross-linking treatments. METHODS The ocular shape of enucleated eyes was photographed(More)
Chain topology has a profound impact on the flow behavior of single macromolecules. For circular polymers, the absence of free ends results in a unique chain architecture compared to linear or branched chains, thereby generating distinct molecular dynamics. Here, we report the direct observation of circular DNA dynamics in transient and steady flows for(More)
A, "Real-time depth sectioning: Isolating the effect of stress on structure development in pressure-driven flow" (2009). Faculty Publications from the Department of Engineering Mechanics. Paper 67. Synopsis Transient structure development at a specific distance from the channel wall in a pressure-driven flow is obtained from a set of real-time measurements(More)
An experimental configuration that combines the powerful capabilities of a short-term shearing apparatus with simultaneous optical and X-ray scattering techniques is demonstrated, connecting the earliest events that occur during shear-induced crystallization of a polymer melt with the subsequent kinetics and morphology development. Oriented precursors are(More)