Reversible wetting of NaCl nanoparticles at relative humidities below deliquescence observed by environmental non-contact AFM

PDF Version Also Available for Download.

Description

The behavior of NaCl nanoparticles as a function of relative humidity (RH) was characterized by depositing particles on a prepared hydrophobic surface and measuring their height via non-contact environmental atomic force microscopy (AFM). Non-contact AFM allows greater sensitivity to changes in the size of particles than does contact AFM or scanning electron microscopy, and greater sensitivity to changes in shape than do mass-based techniques. Crystalline cubic NaCl nanoparticles with sides of 35 to 150 nm were found to reversibly take up water with increasing RH, and to form a liquid-like surface layer of thickness 2 to 4 nm at humidities ... continued below

Creation Information

Bruzewicz, D.A.; Lewis, E.; Ocko, B. M.; McGraw, R. L. & Schwartz, S. E. December 14, 2009.

Context

This article is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided by UNT Libraries Government Documents Department to Digital Library, a digital repository hosted by the UNT Libraries. More information about this article can be viewed below.

Who

People and organizations associated with either the creation of this article or its content.

Provided By

UNT Libraries Government Documents Department

Serving as both a federal and a state depository library, the UNT Libraries Government Documents Department maintains millions of items in a variety of formats. The department is a member of the FDLP Content Partnerships Program and an Affiliated Archive of the National Archives.

Contact Us

What

Descriptive information to help identify this article. Follow the links below to find similar items on the Digital Library.

Description

The behavior of NaCl nanoparticles as a function of relative humidity (RH) was characterized by depositing particles on a prepared hydrophobic surface and measuring their height via non-contact environmental atomic force microscopy (AFM). Non-contact AFM allows greater sensitivity to changes in the size of particles than does contact AFM or scanning electron microscopy, and greater sensitivity to changes in shape than do mass-based techniques. Crystalline cubic NaCl nanoparticles with sides of 35 to 150 nm were found to reversibly take up water with increasing RH, and to form a liquid-like surface layer of thickness 2 to 4 nm at humidities well below the deliquescence point of 75.0% at 20°C. Measurable uptake begins at 70% RH. The maximum thickness of the layer increases with increasing RH for a given particle size and, for a given RH, increases with increasing particle size over the range studied. The liquid-like behavior of the layer is indicated by a reversible “rounding” at the tops of the particles, where the ratio of particle height to radius of curvature increases from zero (flat top) at 68% RH to 0.7 at 74% RH. These observations suggest that a reorganization of mass occurs on the solid NaCl nanoparticle, and hence that the behavior of NaCl aerosol nanoparticles at RH between 70 and 75% RH is more complex than an abrupt first-order phase transition. Theoretical treatments of the phase transition should therefore account for both the presence of a liquid-like layer prior to deliquescence, and the RH-dependent thickness of the layer.

Source

  • American Geophysical Union Fall Meeting; San Francisco, CA; 20091214 through 20091218

Language

Item Type

Identifier

Unique identifying numbers for this article in the Digital Library or other systems.

  • Report No.: BNL--90943-2010-CP
  • Grant Number: DE-AC02-98CH10886
  • Office of Scientific & Technical Information Report Number: 974231
  • Archival Resource Key: ark:/67531/metadc933646

Collections

This article is part of the following collection of related materials.

Office of Scientific & Technical Information Technical Reports

What responsibilities do I have when using this article?

When

Dates and time periods associated with this article.

Creation Date

  • December 14, 2009

Added to The UNT Digital Library

  • Nov. 13, 2016, 7:26 p.m.

Description Last Updated

  • Dec. 12, 2016, 8:41 p.m.

Usage Statistics

When was this article last used?

Yesterday: 1
Past 30 days: 4
Total Uses: 10

Interact With This Article

Here are some suggestions for what to do next.

Enlarge

PDF Version Also Available for Download.

Citations, Rights, Re-Use

Bruzewicz, D.A.; Lewis, E.; Ocko, B. M.; McGraw, R. L. & Schwartz, S. E. Reversible wetting of NaCl nanoparticles at relative humidities below deliquescence observed by environmental non-contact AFM, article, December 14, 2009; United States. (digital.library.unt.edu/ark:/67531/metadc933646/: accessed August 20, 2017), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.