Electrospray Ionization of Polymers: Evaporation, Drop Fission, and Deposited Particle Morphology

The fundamental challenge of nanomanufacturing is to create, control, and assemble enormous quantities of nanoscale objects and distribute them over large surface areas. Electrospray ionization (ESI) has the potential to address this challenge due to its simplicity, applicability to a broad range of materials, and intrinsic scalability. ESI uses high voltages to electrically charge and disperse materials ranging in size from sub-nanometers to micrometers in diameter, which can then be guided and deposited on a substrate. However, the interactions between initial spray parameters and final deposited morphology are not well understood. In this study, we show that when electrospraying polymers, deposited particle size and morphology can be modified through the initial polymer concentration and nozzle-substrate distance. We report the results of electrospraying 0.1% and 0.5% concentrations of poly(acrylic acid) (PAA) onto substrates with 1, 3, and 5 cm nozzle-substrate distances. Scanning electron microscopy showed that deposited particles ranged from less than 10 nm to nearly 200 nm in diameter with tight, multi-modal size distributions. Particle shape and spread on the substrate were also examined. We use physics-based models to show that the size distributions are a function of the evaporation and drop fission during the spray along with the effect of solute concentration gradients within an evaporating drop. This work validates our previously developed models and will lead to future process guidelines.

Electrospray Ionization of Polymers: Evaporation, Drop Fission, and Deposited Particle Morphology1

Journal of Micro and Nano-Manufacturing ◽

10.1115/1.4028505 ◽

2015 ◽

Vol 3 (1) ◽

Cited By ~ 5

Author(s):

Marriner H. Merrill ◽

William R. Pogue ◽

Jared N. Baucom

Keyword(s):

Particle Size ◽

Electrospray Ionization ◽

Solute Concentration ◽

Experimental Results ◽

Size Distributions ◽

Particle Size Distributions ◽

Concentration Gradients ◽

Surface Areas ◽

Fundamental Challenge ◽

Coulomb Fission

The fundamental challenge of nanomanufacturing is to create, control, and place immense quantities of nanoscale objects controllably over large surface areas. Electrospray ionization (ESI) has the potential to address this challenge due to its simplicity, applicability to a broad range of materials, and intrinsic scalability. However, the interactions between electrospray parameters and final deposited morphology are not well understood. Experimental results are combined with physics-based models to explain how observed particle size distributions are caused in the spray by evaporation and Coulomb fission of drops with solute concentration gradients.

Polyacids as Modulators for the Synthesis of UiO-66

Australian Journal of Chemistry ◽

10.1071/ch19271 ◽

2019 ◽

Vol 72 (10) ◽

pp. 848 ◽

Cited By ~ 3

Author(s):

Kyle C. Bentz ◽

Sergio Ayala ◽

Mark Kalaj ◽

Seth M. Cohen

Keyword(s):

Particle Size ◽

Raft Polymerization ◽

Metal Organic Framework ◽

Size Distributions ◽

Particle Size Distributions ◽

Reversible Addition ◽

Metal Organic ◽

Size And Morphology ◽

University Of Oslo

Poly(acrylic acid) (PAA) and poly(vinylbenzoic acid) (PBA) were synthesized via reversible addition–fragmentation chain transfer (RAFT) polymerization and used as modulators for the synthesis of the metal–organic framework (MOF) UiO-66 (UiO=University of Oslo). Whereas typical syntheses of UiO-66 require large excesses of acid modulators, such as acetic acid or benzoic acid, to achieve controlled particle size and morphology of the resulting MOF particles, the use of polymerized acids allows for narrow particle size distributions at sub-stoichiometric quantities of modulator. We show using scanning electron microscopy and dynamic light scattering techniques that polyacids can act as alternative modulators for the growth of UiO-66.

Uniform Chitosan Microparticles Prepared by a Novel Spray-Drying Technique

International Journal of Chemical Engineering ◽

10.1155/2011/267218 ◽

2011 ◽

Vol 2011 ◽

pp. 1-7 ◽

Cited By ~ 24

Author(s):

Wenjie Liu ◽

Winston Duo Wu ◽

Cordelia Selomulya ◽

Xiao Dong Chen

Keyword(s):

Particle Size ◽

Spray Drying ◽

Storage Time ◽

Particle Morphology ◽

Surface Characteristics ◽

Single Step ◽

Drying Temperature ◽

Chitosan Microparticles ◽

Particle size and morphology are important properties of pharmaceutical particles. Preparation of microparticles with uniform particle size and morphology is necessary in order to systematically relate these properties to the release behavior and other functionalities such as drug encapsulation and dissolution. In this study, we successfully prepared monodisperse, nonagglomerated chitosan microparticles in a single step by a novel spray-drying technique. The control of particle size and morphology of spray-dried microparticles was investigated experimentally. Microparticles with larger particle size can be produced when chitosan precursor of higher concentration was used. Storage time of chitosan precursor, drying temperature, and addition of lactose were shown to be crucial parameters that affect the particle morphology. Appropriate choice of the drying temperature and precursor storage time permitted control of the particle morphology, ranging from nearly spherical to cap-shaped. Surface characteristics of the particles can be finely tuned by the amount of lactose added into the chitosan precursor.

Direct manipulation of particle size and morphology of ordered mesoporous silica by flow synthesis

RSC Advances ◽

10.1039/c4ra16679e ◽

2015 ◽

Vol 5 (18) ◽

pp. 13331-13340 ◽

Cited By ~ 27

Author(s):

T. N. Ng ◽

X. Q. Chen ◽

K. L. Yeung

Keyword(s):

Particle Size ◽

Mesoporous Silica ◽

Hollow Spheres ◽

Ordered Mesoporous Silica ◽

Direct Manipulation ◽

Flow Synthesis ◽

Precise Control ◽

Ordered Mesoporous ◽

Flow-synthesis of mesoporous silica allows deliberate and precise control over the size and shapes and enables the preparation of complex microstructures (i.e., hollow spheres).

Preparation of High-Purity Ultrafine α-Al2O3 by Solid-State Reaction at Room Temperature

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.368-372.683 ◽

2008 ◽

Vol 368-372 ◽

pp. 683-685

Author(s):

Cheng Wei Hao ◽

Bo Lin Wu ◽

Ji Yan Li

Keyword(s):

Solid State ◽

High Purity ◽

Solid State Reaction ◽

Room Temperature ◽

Raw Materials ◽

Phase Particle ◽

Phase Transformation Temperature ◽

Size And Morphology ◽

Α Al2o3

Ammonium aluminium carbonate hydroxide (AACH), with a small quantity of γ-AlOOH, was synthesized through solid-state reaction at room temperature using AlCl3·6H2O and NH4HCO3 as raw materials and polyethylene glycol (PEG-10000) as the dispersant. After calcined at 1100°C for 1.5h, α-Al2O3 powders with primary particle sizes of 20~30nm were obtained. The crystal phase, particle size and morphology of the high-purity ultrafine α-Al2O3 were characterized. The results showed that a small quantity of γ-AlOOH in the AACH decomposed and formed crystal seeds. The presence of crystal seeds reduced the nucleation activation energy and therefore reduced the phase transformation temperature.

Prediction of solute concentration gradients during growth of discontinuous precipitates in a Fe-13.5 at.% Zn alloy

Materials Letters ◽

10.1016/j.matlet.2021.130317 ◽

2021 ◽

pp. 130317

Author(s):

Mateusz Chronowski ◽

Jarosław Opara ◽

Olga A. Kogtenkova ◽

Alexander V. Druzhinin ◽

Paweł Zięba

Keyword(s):

Solute Concentration ◽

Concentration Gradients ◽

Zn Alloy

Synthesis and Characterization of a Fe3O4@PNIPAM-Chitosan Nanocomposite and Its Potential Application in Vincristine Delivery

Polymers ◽

10.3390/polym13111704 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1704

Author(s):

Cynthia N. Hernández-Téllez ◽

Ana G. Luque-Alcaraz ◽

Maribel Plascencia-Jatomea ◽

Hiram J. Higuera-Valenzuela ◽

Mabeth Burgos-Hernández ◽

...

Keyword(s):

Fe3o4 Nanoparticles ◽

Release Kinetics ◽

Magnetic Core ◽

Systematic Evaluation ◽

Solution Temperature ◽

Core Shell ◽

Size And Morphology ◽

Thermomagnetic Properties ◽

Release Model

In this research, we conducted a systematic evaluation of the synthesis parameters of a multi-responsive core-shell nanocomposite (Fe3O4 nanoparticles coated by poly(N-isopropylacrylamide) (PNIPAM) in the presence of chitosan (CS) (Fe3O4@PNIPAM-CS). Scanning electron microscopy (SEM) was used to follow the size and morphology of the nanocomposite. The functionalization and the coating of Fe3O4 nanoparticles (Nps) were evaluated by the ζ-potential evolution and Fourier Transform infrared spectroscopy (FTIR). The nanocomposite exhibited a collapsed structure when the temperature was driven above the lower critical solution temperature (LCST), determined by dynamic light scattering (DLS). The LCST was successfully shifted from 33 to 39 °C, which opens the possibility of using it in physiological systems. A magnetometry test was performed to confirm the superparamagnetic behavior at room temperature. The obtained systems allow the possibility to control specific properties, such as particle size and morphology. Finally, we performed vincristine sulfate loading and release tests. Mathematical analysis reveals a two-stage structural-relaxation release model beyond the LCST. In contrast, a temperature of 25 °C promotes the diffusional release model. As a result, a more in-depth comprehension of the release kinetics was achieved. The synthesis and study of a magnetic core-shell nanoplatform offer a smart material as an alternative targeted release therapy due to its thermomagnetic properties.

Dehumidified Air-Assisted Spray-Drying of Cloudy Beetroot Juice at Low Temperature

Applied Sciences ◽

10.3390/app11146578 ◽

2021 ◽

Vol 11 (14) ◽

pp. 6578

Author(s):

Aleksandra Jedlińska ◽

Alicja Barańska ◽

Dorota Witrowa-Rajchert ◽

Ewa Ostrowska-Ligęza ◽

Katarzyna Samborska

Keyword(s):

Particle Size ◽

Physicochemical Properties ◽

Spray Drying ◽

Low Temperatures ◽

Beetroot Juice ◽

Size And Morphology ◽

Tapped Density ◽

Lower Loss ◽

Better Than

This paper discusses the physicochemical properties of powders obtained by spray drying of cloudy beetroot juice, using dehumidified air in variants with or without carriers. The inlet air temperature was 130 °C or 90 °C, and the addition of the carriers was at a ratio of juice to carrier solids of 3:2. In the obtained powders, the following physicochemical properties were determined: water content and water activity, apparent density, loose and tapped density, porosity, flowability, particle size and morphology, and the content and retention of betalains. It was possible to dry cloudy beetroot juice without the use of carriers at low temperatures (90 or 130 °C). The 100% beetroot powders were characterized by satisfactory physicochemical properties, often better than those with carriers (including lower hygroscopicity and higher color saturation and yield). A lower loss of betalains was found for the powders with the addition of carriers. The best process yields were obtained for the powder without carriers at 130 °C and 90 °C.

EFFECTS OF OSMOTIC GRADIENTS ACROSS THE PRIMATE PLACENTAL UPON FETAL AND PLACENTAL WATER CONTENTS

PEDIATRICS ◽

10.1542/peds.34.3.407 ◽

1964 ◽

Vol 34 (3) ◽

pp. 407-411

Author(s):

Paul D. Bruns ◽

Andre E. Hellegers ◽

A. Elmore Seeds ◽

Richard E. Behrman ◽

Frederick C. Battaglia

Keyword(s):

Sodium Chloride ◽

Amniotic Fluid ◽

Rhesus Monkeys ◽

Solute Concentration ◽

Total Water Content ◽

Total Water ◽

Concentration Gradients ◽

Maternal Circulation ◽

Total Body ◽

Water Contents

Infusions of 2.7 g/100 ml sodium chloride or 30 g/100 ml disaccharide solutions into the maternal circulation of pregnant rhesus monkeys produced a significant reduction in fetal and placental total water content. At the same time large transplacental total solute concentration gradients were produced. The injection of sucrose into the amniotic fluid of pregnant rhesus monkeys produced a reduction in fetal total body water alone. The significance of these differences is discussed.

Synthesis and Characterization of Calcium Tartrate Dihydrate Nanoparticles

International Journal of Nanoscience ◽

10.1142/s0219581x15500131 ◽

2015 ◽

Vol 14 (04) ◽

pp. 1550013 ◽

Cited By ~ 2

Author(s):

Urvisha Tarpara ◽

Poorvesh Vyas ◽

Mihir J. Joshi

Keyword(s):

Average Crystallite Size ◽

Powder Xrd ◽

Xrd Pattern ◽

Crystalline Materials ◽

Transmission Electron ◽

Calcium Tartrate ◽

Wet Chemical ◽

Calcium tartrate finds various applications. In the present study, calcium tartrate nanoparticles were synthesized by wet chemical method using surfactant mediated approach. The powder XRD pattern revealed the typical broadening of peaks indicating the nanostructured nature. The average crystallite size was calculated by applying the Scherrer's formula to powder XRD pattern and was found in the range of 22.8–23.9 nm. The particle size and morphology of the synthesized nanoparticles was confirmed by using transmission electron microscopy (TEM). FTIR spectroscopy was used to confirm the presence of various functional groups. From TGA, it was found that calcium tartrate nanoparticles remained stable up to 120°C and were having two water molecules associated with them. The results are compared with the bulk crystalline materials available in the literature.