scholarly journals Homogeneous Gelation Leads to Nanowire Forests in the Transition Between Electrospray and Electrospinning

2020 ◽  
Author(s):  
Lin Lei ◽  
Shensheng Chen ◽  
Catherine Nachtigal ◽  
Tyler Moy ◽  
Xin Yong ◽  
...  
Keyword(s):  
Dissipative Particle Dynamics ◽  
Solution Temperature ◽  
Specific Viscosity ◽  
Critical Solution Temperature ◽  
Electrostatic Deposition ◽  
Low Viscosity ◽  
Gel Phase ◽  
Spatially Varying ◽  
Electrostatic Spray ◽  
Varying Viscosity

<p>The morphology of coatings created by electrostatic deposition can be generally divided into three categories: wire mats (electrospinning), particles (electrostatic spray, electrospray deposition(ESD)), and films (all low-viscosity applications). There should exist nanowire forests as a mixture of wire and particulate deposition. Such a morphology has yet to be observed experimentally, which we propose is the result of spatially-varying viscosity in sprayed droplets. We utilized electrostatic dissipative particle dynamics (DPD) and ESD to explore the spray of methylcellulose (MC) in water:ethanol mixtures. MC possesses a lower critical solution temperature (LCST) in water and water:ethanol blends. DPD simulations reveal that the barrier to forming nanowire forests is the directional nature of evaporation, but they should form were evaporation homogeneous. In ESD conducted above the LCST, MC and water phase separate concurrently with the rapid evaporation of ethanol, forming a homogeneous gel phase. This gel can undergo the elongation of electrospinning on a drop-by-drop basis to create forests of individual nanowires. Our study indicates that this homogenous evolution of viscosity is necessary for nanowire forest formation and that the specific viscosity (along with droplet size) further controls the morphology of the forests.</p>

scholarly journals Homogeneous Gelation Leads to Nanowire Forests in the Transition Between Electrospray and Electrospinning

2020 ◽  
Author(s):  
Lin Lei ◽  
Shensheng Chen ◽  
Catherine Nachtigal ◽  
Tyler Moy ◽  
Xin Yong ◽  
...  
Keyword(s):  
Dissipative Particle Dynamics ◽  
Solution Temperature ◽  
Specific Viscosity ◽  
Critical Solution Temperature ◽  
Electrostatic Deposition ◽  
Low Viscosity ◽  
Gel Phase ◽  
Spatially Varying ◽  
Electrostatic Spray ◽  
Varying Viscosity

<p>The morphology of coatings created by electrostatic deposition can be generally divided into three categories: wire mats (electrospinning), particles (electrostatic spray, electrospray deposition(ESD)), and films (all low-viscosity applications). There should exist nanowire forests as a mixture of wire and particulate deposition. Such a morphology has yet to be observed experimentally, which we propose is the result of spatially-varying viscosity in sprayed droplets. We utilized electrostatic dissipative particle dynamics (DPD) and ESD to explore the spray of methylcellulose (MC) in water:ethanol mixtures. MC possesses a lower critical solution temperature (LCST) in water and water:ethanol blends. DPD simulations reveal that the barrier to forming nanowire forests is the directional nature of evaporation, but they should form were evaporation homogeneous. In ESD conducted above the LCST, MC and water phase separate concurrently with the rapid evaporation of ethanol, forming a homogeneous gel phase. This gel can undergo the elongation of electrospinning on a drop-by-drop basis to create forests of individual nanowires. Our study indicates that this homogenous evolution of viscosity is necessary for nanowire forest formation and that the specific viscosity (along with droplet size) further controls the morphology of the forests.</p>

scholarly journals Homogeneous Gelation Leads to Nanowire Forests in the Transition Between Electrospray and Electrospinning

2020 ◽  
Author(s):  
Lin Lei ◽  
Shensheng Chen ◽  
Catherine Nachtigal ◽  
Tyler Moy ◽  
Xin Yong ◽  
...  
Keyword(s):  
Dissipative Particle Dynamics ◽  
Solution Temperature ◽  
Specific Viscosity ◽  
Critical Solution Temperature ◽  
Electrostatic Deposition ◽  
Low Viscosity ◽  
Gel Phase ◽  
Spatially Varying ◽  
Electrostatic Spray ◽  
Varying Viscosity

<p>The morphology of coatings created by electrostatic deposition can be generally divided into three categories: wire mats (electrospinning), particles (electrostatic spray, electrospray deposition(ESD)), and films (all low-viscosity applications). There should exist nanowire forests as a mixture of wire and particulate deposition. Such a morphology has yet to be observed experimentally, which we propose is the result of spatially-varying viscosity in sprayed droplets. We utilized electrostatic dissipative particle dynamics (DPD) and ESD to explore the spray of methylcellulose (MC) in water:ethanol mixtures. MC possesses a lower critical solution temperature (LCST) in water and water:ethanol blends. DPD simulations reveal that the barrier to forming nanowire forests is the directional nature of evaporation, but they should form were evaporation homogeneous. In ESD conducted above the LCST, MC and water phase separate concurrently with the rapid evaporation of ethanol, forming a homogeneous gel phase. This gel can undergo the elongation of electrospinning on a drop-by-drop basis to create forests of individual nanowires. Our study indicates that this homogenous evolution of viscosity is necessary for nanowire forest formation and that the specific viscosity (along with droplet size) further controls the morphology of the forests.</p>

Selective Hydrogen Bonding Controls Temperature Response of Layer-by-Layer Upper Critical Solution Temperature Micellar Assemblies

Soft Matter ◽  
2021 ◽  
Author(s):  
Aliaksei Aliakseyeu ◽  
Victoria Albright ◽  
Danielle Yarbrough ◽  
Samantha Hernandez ◽  
Qing Zhou ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Methacrylic Acid ◽  
Temperature Response ◽  
Solution Temperature ◽  
Layer By Layer ◽  
Critical Solution Temperature ◽  
Hydrogen Bonding Interactions ◽  
Upper Critical Solution Temperature ◽  
Lbl Films

This work establishes a correlation between the selectivity of hydrogen-bonding interactions and the functionality of micelle-containing layer-by-layer (LbL) assemblies. Specifically, we explore LbL films formed by assembly of poly(methacrylic acid)...

scholarly journals Thermo- and Photoresponsive Behaviors of Dual-Stimuli-Responsive Organogels Consisting of Homopolymers of Coumarin-Containing Methacrylate

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 329
Author(s):  
Seidai Okada ◽  
Eriko Sato
Keyword(s):  
Functional Group ◽  
Solution Temperature ◽  
Stimuli Responsive ◽  
Critical Solution Temperature ◽  
Equilibrium Degree ◽  
Stimuli Responsive Polymers ◽  
Responsive Polymers ◽  
Dual Functional ◽  
Wide Range ◽  
Increasing Temperature

Coumarin-containing vinyl homopolymers, such as poly(7-methacryloyloxycoumarin) (P1a) and poly(7-(2′-methacryloyloxyethoxy)coumarin) (P1b), show a lower critical solution temperature (LCST) in chloroform, which can be controlled by the [2 + 2] photochemical cycloaddition of the coumarin moiety, and they are recognized as monofunctional dual-stimuli-responsive polymers. A single functional group of monofunctional dual-stimuli-responsive polymers responds to dual stimuli and can be introduced more uniformly and densely than those of dual-functional dual-stimuli-responsive polymers. In this study, considering a wide range of applications, organogels consisting of P1a and P1b, i.e., P1a-gel and P1b-gel, respectively, were synthesized, and their thermo- and photoresponsive behaviors in chloroform were investigated in detail. P1a-gel and P1b-gel in a swollen state (transparent) exhibited phase separation (turbid) through a temperature jump and reached a shrunken state (transparent), i.e., an equilibrium state, over time. Moreover, the equilibrium degree of swelling decreased non-linearly with increasing temperature. Furthermore, different thermoresponsive sites were photopatterned on the organogel through the photodimerization of the coumarin unit. The organogels consisting of homopolymers of coumarin-containing methacrylate exhibited unique thermo- and photoresponsivities and behaved as monofunctional dual-stimuli-responsive organogels.

scholarly journals Synthesis of a thermoresponsive crosslinked MEO2MA polymer coating on microclusters of iron oxide nanoparticles

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alejandro Lapresta-Fernández ◽  
Alfonso Salinas-Castillo ◽  
Luis Fermín Capitán-Vallvey
Keyword(s):  
Iron Oxide ◽  
Synthesis Temperature ◽  
Water Soluble ◽  
Covalent Attachment ◽  
Solution Temperature ◽  
Tetraethylene Glycol ◽  
Critical Solution Temperature ◽  
Large Size ◽  
Transmission Electron ◽  
Azo Initiator

AbstractEncapsulation of magnetic nanoparticles (MNPs) of iron (II, III) oxide (Fe3O4) with a thermopolymeric shell of a crosslinked poly(2-(2-methoxyethoxy)ethyl methacrylate) P(MEO2MA) is successfully developed. Magnetic aggregates of large size, around 150–200 nm are obtained during the functionalization of the iron oxide NPs with vinyl groups by using 3-butenoic acid in the presence of a water soluble azo-initiator and a surfactant, at 70 °C. These polymerizable groups provide a covalent attachment of the P(MEO2MA) shell on the surface of the MNPs while a crosslinked network is achieved by including tetraethylene glycol dimethacrylate in the precipitation polymerization synthesis. Temperature control is used to modulate the swelling-to-collapse transition volume until a maximum of around 21:1 ratio between the expanded: shrunk states (from 364 to 144 nm in diameter) between 9 and 49 °C. The hybrid Fe3O4@P(MEO2MA) microgel exhibits a lower critical solution temperature of 21.9 °C below the corresponding value for P(MEO2MA) (bulk, 26 °C). The MEO2MA coating performance in the hybrid microgel is characterized by dynamic light scattering and transmission electron microscopy. The content of preformed MNPs [up to 30.2 (wt%) vs. microgel] was established by thermogravimetric analysis while magnetic properties by vibrating sample magnetometry.

A polyelectrolyte-containing copolymer with a gas-switchable lower critical solution temperature-type phase transition

2019 ◽  
Vol 10 (2) ◽  
pp. 260-266 ◽  
Author(s):  
Jin-Jin Li ◽  
Yin-Ning Zhou ◽  
Zheng-Hong Luo ◽  
Shiping Zhu
Keyword(s):  
Phase Transition ◽  
Cloud Point ◽  
Lower Critical Solution Temperature ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Type Phase

A polyelectrolyte-containing copolymer with a CO2/N2-switchable cloud point, resulting from the gas-induced alternation of hydrophilicity, was prepared.

Dual-temperature and pH responsive (ethylene glycol)-based nanogels via structural design

2014 ◽  
Vol 5 (8) ◽  
pp. 3061-3070 ◽  
Author(s):  
Yohei Kotsuchibashi ◽  
Ravin Narain
Keyword(s):  
Carboxylic Acid ◽  
Ethylene Glycol ◽  
Salt Concentration ◽  
Structural Design ◽  
Solution Temperature ◽  
Ph Responsive ◽  
Solution Ph ◽  
Critical Solution Temperature ◽  
Carboxylic Acid Groups ◽  
The Core

Dual-temperature and pH responsive (ethylene glycol)-based nanogels were synthesized. Both the core and the shell of the nanogels showed a lower critical solution temperature (LCST) and the LCST of the shell was strongly affected by the solution pH and salt concentration due to the presence of carboxylic acid groups at the nanogel surface.

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