High frame-rate imaging of the shape oscillations and spreading dynamics of picolitre droplets impacting on a surface

Lauren P McCarthy; Jonathan P Reid; Jim S Walker

doi:10.1063/5.0174511

High frame-rate imaging of the shape oscillations and spreading dynamics of picolitre droplets impacting on a surface

Lauren P McCarthy, Jonathan P Reid^*, Jim S Walker^*

^*Corresponding author for this work

Research output: Contribution to journal › Article (Academic Journal) › peer-review

3 Citations (Scopus)

Abstract

The post-impact dynamics and spreading rates of picolitre liquid droplets on surfaces are critical to many practical and industrial applications, as well as respiratory disease transmission mechanisms. Here we use a high framerate imaging method to explore the shape oscillations and spreading of individual ~10-180 pL volume droplets (corresponding to ~30-70 µm in initial droplet diameter) impacting on a surface under ambient conditions with 10 µs temporal resolution. The method allows the surface tension to be accurately extracted from the measured frequency of post-impact shape oscillations for sessile droplets in this size range with surface tensions greater than 40 mN m-1 and viscosities up to at least 3.2 mPa s. The Tanner’s law model for predicting sessile droplet spreading rates provides an accurate account of the ‘steady-state’ spreading rate for all droplets with surface tensions in the range 22–73 mN m-1 studied here. However, Tanner’s law does not account for the delay in the onset of spreading observed for droplets in this size range, caused by competition between shape oscillations and spreading governing the morphology at short time periods, particularly for surface tensions >22 mN m-1.

Original language	English
Article number	122010
Number of pages	27
Journal	Physics of Fluids
Volume	35
Issue number	12
DOIs	https://doi.org/10.1063/5.0174511 https://doi.org/10.5523/bris.882ciio84luc2k99urkp5s2yb
Publication status	Published - 1 Dec 2023

Bibliographical note

Funding Information:
The authors acknowledge Jamie Mclauchlan for their helpful feedback and discussion. The authors also acknowledge the Bristol Aerosols and Colloids Instrument Centre (BACIC), for use of the Krüss Drop Shape Analyzer (DSA100). LPM acknowledges funding from EPSRC (EP/S023593/1).

Funding Information:
The authors acknowledge Jamie Mclauchlan for their helpful feedback and discussion. The authors also acknowledge the Bristol Aerosols and Colloids Instrument Centre (BACIC), for use of the Krüss Drop Shape Analyzer (DSA100). LPM acknowledges funding from EPSRC (EP/S023593/1).

Publisher Copyright:
© 2023 Author(s).

Access to Document

10.1063/5.0174511Licence: CC BY
10.5523/bris.882ciio84luc2k99urkp5s2ybLicence: Other

Handle.net

Persistent link

Cite this

@article{f152016505ed4cfca160bca23f4a26e3,

title = "High frame-rate imaging of the shape oscillations and spreading dynamics of picolitre droplets impacting on a surface",

abstract = "The post-impact dynamics and spreading rates of picolitre liquid droplets on surfaces are critical to many practical and industrial applications, as well as respiratory disease transmission mechanisms. Here we use a high framerate imaging method to explore the shape oscillations and spreading of individual ~10-180 pL volume droplets (corresponding to ~30-70 µm in initial droplet diameter) impacting on a surface under ambient conditions with 10 µs temporal resolution. The method allows the surface tension to be accurately extracted from the measured frequency of post-impact shape oscillations for sessile droplets in this size range with surface tensions greater than 40 mN m-1 and viscosities up to at least 3.2 mPa s. The Tanner{\textquoteright}s law model for predicting sessile droplet spreading rates provides an accurate account of the {\textquoteleft}steady-state{\textquoteright} spreading rate for all droplets with surface tensions in the range 22–73 mN m-1 studied here. However, Tanner{\textquoteright}s law does not account for the delay in the onset of spreading observed for droplets in this size range, caused by competition between shape oscillations and spreading governing the morphology at short time periods, particularly for surface tensions >22 mN m-1.",

author = "McCarthy, {Lauren P} and Reid, {Jonathan P} and Walker, {Jim S}",

note = "Funding Information: The authors acknowledge Jamie Mclauchlan for their helpful feedback and discussion. The authors also acknowledge the Bristol Aerosols and Colloids Instrument Centre (BACIC), for use of the Kr{\"u}ss Drop Shape Analyzer (DSA100). LPM acknowledges funding from EPSRC (EP/S023593/1). Funding Information: The authors acknowledge Jamie Mclauchlan for their helpful feedback and discussion. The authors also acknowledge the Bristol Aerosols and Colloids Instrument Centre (BACIC), for use of the Kr{\"u}ss Drop Shape Analyzer (DSA100). LPM acknowledges funding from EPSRC (EP/S023593/1). Publisher Copyright: {\textcopyright} 2023 Author(s).",

year = "2023",

month = dec,

day = "1",

doi = "10.1063/5.0174511",

language = "English",

volume = "35",

journal = "Physics of Fluids",

issn = "1070-6631",

publisher = "American Institute of Physics (AIP)",

number = "12",

}

TY - JOUR

T1 - High frame-rate imaging of the shape oscillations and spreading dynamics of picolitre droplets impacting on a surface

AU - McCarthy, Lauren P

AU - Reid, Jonathan P

AU - Walker, Jim S

N1 - Funding Information: The authors acknowledge Jamie Mclauchlan for their helpful feedback and discussion. The authors also acknowledge the Bristol Aerosols and Colloids Instrument Centre (BACIC), for use of the Krüss Drop Shape Analyzer (DSA100). LPM acknowledges funding from EPSRC (EP/S023593/1). Funding Information: The authors acknowledge Jamie Mclauchlan for their helpful feedback and discussion. The authors also acknowledge the Bristol Aerosols and Colloids Instrument Centre (BACIC), for use of the Krüss Drop Shape Analyzer (DSA100). LPM acknowledges funding from EPSRC (EP/S023593/1). Publisher Copyright: © 2023 Author(s).

PY - 2023/12/1

Y1 - 2023/12/1

N2 - The post-impact dynamics and spreading rates of picolitre liquid droplets on surfaces are critical to many practical and industrial applications, as well as respiratory disease transmission mechanisms. Here we use a high framerate imaging method to explore the shape oscillations and spreading of individual ~10-180 pL volume droplets (corresponding to ~30-70 µm in initial droplet diameter) impacting on a surface under ambient conditions with 10 µs temporal resolution. The method allows the surface tension to be accurately extracted from the measured frequency of post-impact shape oscillations for sessile droplets in this size range with surface tensions greater than 40 mN m-1 and viscosities up to at least 3.2 mPa s. The Tanner’s law model for predicting sessile droplet spreading rates provides an accurate account of the ‘steady-state’ spreading rate for all droplets with surface tensions in the range 22–73 mN m-1 studied here. However, Tanner’s law does not account for the delay in the onset of spreading observed for droplets in this size range, caused by competition between shape oscillations and spreading governing the morphology at short time periods, particularly for surface tensions >22 mN m-1.

AB - The post-impact dynamics and spreading rates of picolitre liquid droplets on surfaces are critical to many practical and industrial applications, as well as respiratory disease transmission mechanisms. Here we use a high framerate imaging method to explore the shape oscillations and spreading of individual ~10-180 pL volume droplets (corresponding to ~30-70 µm in initial droplet diameter) impacting on a surface under ambient conditions with 10 µs temporal resolution. The method allows the surface tension to be accurately extracted from the measured frequency of post-impact shape oscillations for sessile droplets in this size range with surface tensions greater than 40 mN m-1 and viscosities up to at least 3.2 mPa s. The Tanner’s law model for predicting sessile droplet spreading rates provides an accurate account of the ‘steady-state’ spreading rate for all droplets with surface tensions in the range 22–73 mN m-1 studied here. However, Tanner’s law does not account for the delay in the onset of spreading observed for droplets in this size range, caused by competition between shape oscillations and spreading governing the morphology at short time periods, particularly for surface tensions >22 mN m-1.

U2 - 10.1063/5.0174511

DO - 10.1063/5.0174511

M3 - Article (Academic Journal)

SN - 1070-6631

VL - 35

JO - Physics of Fluids

JF - Physics of Fluids

IS - 12

M1 - 122010

ER -

High frame-rate imaging of the shape oscillations and spreading dynamics of picolitre droplets impacting on a surface

Abstract

Bibliographical note

Access to Document

Handle.net

Fingerprint

Cite this