Investigation of gel formation and volatilization of acetate acid in magnesium acetate droplets by the optical tweezers

Xi Juan Lv, Yang Wang, Chen Cai, Shu Feng Pang, Jia Bi Ma*, Yun Hong Zhang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)

Abstract

Hygroscopicity and volatility of single magnesium acetate (MgAc2) aerosol particles at various relative humidities (RHs) are studied by a single-beam optical tweezers, and refractive indices (RIs) and morphology are characterized by cavity enhanced Raman spectroscopy. Gel formation and volatilization of acetate acid (HAc) in MgAc2 droplets are observed. Due to the formation of amorphous gel structure, water transposition in droplets at RH < 50% is significantly impeded on a time scale of 140,000 s. Different phase transition at RH < 10% is proposed to explain the distinct water loss after the gel formation. To compare volatilization of HAc in different systems, MgAc2 and sodium acetate (NaAc) droplets are maintained at several different stable RHs during up to 86,000 s. At RH ≈ 74%, magnesium hydroxide (Mg(OH)2) inclusions are formed in MgAc2 droplets due to the volatilization of HAc, and whispering gallery modes (WGMs) of MgAc2 droplets in the Raman spectrum quench after 50,000 s. In sharp contrast, after 86,000 s at RH ≈ 70%, NaAc droplets are in well-mixed liquid states, containing soluble sodium hydroxide (NaOH). At this state, the RI of NaAc droplet is increased, and the quenching of WGMs is not observable.

Original languageEnglish
Pages (from-to)179-185
Number of pages7
JournalSpectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy
Volume200
DOIs
Publication statusPublished - 5 Jul 2018

Keywords

  • Aerosol particles
  • Amorphous gel structure
  • Optical tweezers
  • Refractive index
  • Volatilization of acetate acid

Fingerprint

Dive into the research topics of 'Investigation of gel formation and volatilization of acetate acid in magnesium acetate droplets by the optical tweezers'. Together they form a unique fingerprint.

Cite this