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

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.

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

Volume 2B: Advanced Manufacturing ◽

10.1115/imece2014-37119 ◽

2014 ◽

Author(s):

Marriner H. Merrill ◽

William R. Pogue ◽

Jared N. Baucom

Keyword(s):

Electrospray Ionization ◽

Polymer Concentration ◽

Particle Morphology ◽

Solute Concentration ◽

Spray Parameters ◽

Size Distributions ◽

Concentration Gradients ◽

Surface Areas ◽

Particle Size And Morphology ◽

Size And 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.

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Particle Size Distributions, Hygroscopicities, Surface Factors, Colloid Contents, and Total Surface Areas of Ceramic Raw Materials and the Relations among Them

Journal of the Ceramic Association Japan ◽

10.2109/jcersj1950.64.726_151 ◽

1956 ◽

Vol 64 (726) ◽

pp. 151-161

Author(s):

Y. SHIRAKI

Keyword(s):

Particle Size ◽

Raw Materials ◽

Size Distributions ◽

Particle Size Distributions ◽

Surface Areas

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Uncertainty in the Surface Area of Crushed Glass in Rate Calculations

MRS Proceedings ◽

10.1557/opl.2015.331 ◽

2015 ◽

Vol 1744 ◽

pp. 145-152

Author(s):

William L. Ebert ◽

Charles L. Crawford ◽

Carol M. Jantzen

Keyword(s):

Particle Size ◽

Surface Area ◽

Size Fraction ◽

Mesh Size ◽

Glass Mass ◽

Size Distributions ◽

Particle Size Distributions ◽

Test Response ◽

Surface Areas ◽

Opposing Effects

ABSTRACTSeries of 7-day Product Consistency Tests (PCTs) were conducted with ARM-1 glass using the -100+200 mesh size fraction and several sub-fractions to measure the sensitivity of the test response to the distribution of particle sizes. Separate samples were prepared for testing by dry sieving and wet sieving, and the particle size distributions and PCT responses were measured for each fraction. Triplicate tests were conducted at 90 °C using a water/glass mass ratio of 10.0 with each size fraction. Test results are evaluated regarding the sensitivity of the test response to the particle size distributions and, conversely, the uncertainty due to calculating the surface areas (and dissolution rates) by modeling the particles as spheres. These analyses show the solution feedback effects of dissolved glass constituents (i.e., the reaction affinity) counteract the effects of the glass surface areas provided by different particle size distributions on the test response. The opposing effects of the surface area on the amount of glass dissolved and on the glass dissolution rate moderate the sensitivity of the PCT response to the particle size distribution.

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