Tunable Nanopatterns via the Constrained Dewetting of Polymer Brushes

Coarse-grained molecular dynamics simulations were used to investigate the morphology and dynamics of nanopatterns formed by grafted polymer brushes on a nonadsorbing substrate as a result of constrained dewetting. As a good solvent is made to gradually evaporate, polymer brushes with low to moderate grafting density collapse into discrete nanosized aggregates, with different types of nanopatterns possible, including pancake micelles and holey layers. The type of pattern, the size and number of features, and their dynamics depend on the grafting density of the polymer brush and amount of good solvent adsorbed. The final pattern morphology depends primarily on the total amount of material adsorbed to the surface, including both polymer and solvent. This result suggests the possibility for the use of polymer brushes as surfaces with reversibly tunable nanopatterns

Tunable Nanopatterns via the Constrained Dewetting of Polymer Brushes

Coarse-grained molecular dynamics simulations were used to investigate the morphology and dynamics of nanopatterns formed by grafted polymer brushes on a nonadsorbing substrate as a result of constrained dewetting. As a good solvent is made to gradually evaporate, polymer brushes with low to moderate grafting density collapse into discrete nanosized aggregates, with different types of nanopatterns possible, including pancake micelles and holey layers. The type of pattern, the size and number of features, and their dynamics depend on the grafting density of the polymer brush and amount of good solvent adsorbed. The final pattern morphology depends primarily on the total amount of material adsorbed to the surface, including both polymer and solvent. This result suggests the possibility for the use of polymer brushes as surfaces with reversibly tunable nanopatterns

Tunable Nanopatterns via the Constrained Dewetting of Polymer Brushes

Coarse-grained molecular dynamics simulations were used to investigate the morphology and dynamics of nanopatterns formed by grafted polymer brushes on a nonadsorbing substrate as a result of constrained dewetting. As a good solvent is made to gradually evaporate, polymer brushes with low to moderate grafting density collapse into discrete nanosized aggregates, with different types of nanopatterns possible, including pancake micelles and holey layers. The type of pattern, the size and number of features, and their dynamics depend on the grafting density of the polymer brush and amount of good solvent adsorbed. The final pattern morphology depends primarily on the total amount of material adsorbed to the surface, including both polymer and solvent. This result suggests the possibility for the use of polymer brushes as surfaces with reversibly tunable nanopatterns

Tunable Nanopatterns via the Constrained Dewetting of Polymer Brushes

Coarse-grained molecular dynamics simulations were used to investigate the morphology and dynamics of nanopatterns formed by grafted polymer brushes on a nonadsorbing substrate as a result of constrained dewetting. As a good solvent is made to gradually evaporate, polymer brushes with low to moderate grafting density collapse into discrete nanosized aggregates, with different types of nanopatterns possible, including pancake micelles and holey layers. The type of pattern, the size and number of features, and their dynamics depend on the grafting density of the polymer brush and amount of good solvent adsorbed. The final pattern morphology depends primarily on the total amount of material adsorbed to the surface, including both polymer and solvent. This result suggests the possibility for the use of polymer brushes as surfaces with reversibly tunable nanopatterns

Tunable Nanopatterns via the Constrained Dewetting of Polymer Brushes

Coarse-grained molecular dynamics simulations were used to investigate the morphology and dynamics of nanopatterns formed by grafted polymer brushes on a nonadsorbing substrate as a result of constrained dewetting. As a good solvent is made to gradually evaporate, polymer brushes with low to moderate grafting density collapse into discrete nanosized aggregates, with different types of nanopatterns possible, including pancake micelles and holey layers. The type of pattern, the size and number of features, and their dynamics depend on the grafting density of the polymer brush and amount of good solvent adsorbed. The final pattern morphology depends primarily on the total amount of material adsorbed to the surface, including both polymer and solvent. This result suggests the possibility for the use of polymer brushes as surfaces with reversibly tunable nanopatterns

Tunable Nanopatterns via the Constrained Dewetting of Polymer Brushes

Coarse-grained molecular dynamics simulations were used to investigate the morphology and dynamics of nanopatterns formed by grafted polymer brushes on a nonadsorbing substrate as a result of constrained dewetting. As a good solvent is made to gradually evaporate, polymer brushes with low to moderate grafting density collapse into discrete nanosized aggregates, with different types of nanopatterns possible, including pancake micelles and holey layers. The type of pattern, the size and number of features, and their dynamics depend on the grafting density of the polymer brush and amount of good solvent adsorbed. The final pattern morphology depends primarily on the total amount of material adsorbed to the surface, including both polymer and solvent. This result suggests the possibility for the use of polymer brushes as surfaces with reversibly tunable nanopatterns

Tunable Nanopatterns via the Constrained Dewetting of Polymer Brushes

Coarse-grained molecular dynamics simulations were used to investigate the morphology and dynamics of nanopatterns formed by grafted polymer brushes on a nonadsorbing substrate as a result of constrained dewetting. As a good solvent is made to gradually evaporate, polymer brushes with low to moderate grafting density collapse into discrete nanosized aggregates, with different types of nanopatterns possible, including pancake micelles and holey layers. The type of pattern, the size and number of features, and their dynamics depend on the grafting density of the polymer brush and amount of good solvent adsorbed. The final pattern morphology depends primarily on the total amount of material adsorbed to the surface, including both polymer and solvent. This result suggests the possibility for the use of polymer brushes as surfaces with reversibly tunable nanopatterns

Elucidation of Novel Nanostructures by Time-Lapse Monitoring of Polystyrene-<i>block</i>-Polyvinylpyridine under Chemical Treatment

Nanoscale micellar structures of polystyrene-<i>block</i>-polyvinylpyridine (PS-<i>b</i>-PVP) diblock copolymers have proven their effectiveness in lithography and biological detection by serving as a choice material to produce nanoscale guides and delivery systems in a straightforward and rapid manner through self-assembly. Such applications can greatly benefit from having high versatility for the selection of template sizes (pattern repeat spacing) and shapes (pattern geometry), especially when reaching a size regime that conventional top-down fabrication techniques may not readily be able to provide desired feature dimensions. Selective chemical treatments of the diblock copolymers are one of the useful methods yielding a rich set of nanoscale features on PS-<i>b</i>-PVP. Exposure to selective vapor can induce reorganization of the polymeric chains of PS-<i>b</i>-PVP and alter the original micellar nanostructures. In this Article, we identify for the first time a host of new nanostructures formed at different stages of chloroform vapor annealing by performing time-lapse atomic force microscopy measurements. We determine key, time-dependent, topological parameters defining each nanostructure and present the likely scenario of polymeric chain reorganization during the morphological evolution of the diblock polymer nanodomains over time. We also ascertain intermediate morphological states containing the characteristic nanostructures from two consecutive phases as well as transition states appearing for a short time in between two subsequent phases. These research efforts may not only provide insight into the domain evolution steps of the micellar to the cylindrical structures of PS-<i>b</i>-PVP but may also be technologically advantageous for subwavelength mask design in nanolithography and high-density array fabrication in high throughput biodetection

<i>Rhodiola rosea</i> extended lifespan when the SIR2 and IIS pathways are blocked.

<p><i>Rhodiola rosea</i> extended lifespan in the absence the insulin receptor substrate in both <b>A</b>, males, <i>P</i> = 0.004, and <b>B</b>, females, <i>P</i> = 0.0004. The extract also extended lifespan in the absence of the principal <i>Drosophila</i> Sir2 protein, dSIR2, in both <b>C</b>, males, <i>P</i><0.0001 and <b>D</b>, females, <i>P</i><0.05. <i>P</i>-values were calculated with the Mantel-Cox Log-Rank test. Increases in mean lifespan due to <i>R. rosea</i> feeding were as follows: <i>chico¹</i> males: 14%; <i>chico¹</i> females: 9%; <i>dSir2</i> males: 27%, <i>dSir2</i> females: 11%. Sample sizes for the control groups and treated groups respectively were as follows: <i>chico¹</i> males: 113, 114; <i>chico¹</i> females: 119, 118; <i>dSir2</i> males: 196, 193, <i>dSir2</i> females: 197, 191.</p

The effect of <i>Rhodiola rosea</i> on the tolerance towards starvation, desiccation, and heat.

<p>A 2-week feeding of <i>R. rosea</i> had no ability to protect males or female flies against <b>A, B,</b> desiccation or <b>C, D,</b> starvation. <i>P</i>>0.05 for all groups. Mantel-Cox Log-Rank test. Sample sizes for the control groups and treated groups respectively were as follows: desiccation males: 114, 118; desiccation females: 94, 101; starvation males: 120, 118; starvation females: 120, 120. <b>E.. </b><i>Rhodiola rosea</i> did not protect males against exposure to 37°C, but did so in <b>F.</b> females, <i>P</i><0.0001, Mantel-Cox Log-Rank test. Sample sizes for the control groups and treated groups respectively were as follows: males: 120, 120; females: 120, 119. <b>G.. </b><i>Rhodiola rosea</i> had had no effect of HSP70 expression but <b>H.</b> down-regulated HSP22 in males, <i>P</i> = 0.004, Mann-Whitney nonparametric test, n = 5 groups of 25 flies for the controls and 6 groups of 25 flies for the treated flies.</p