In-Channel Responsive Surface Wettability for Reversible and Multiform Emulsion Droplet Preparation and Applications

Lanhui Li, Zhibin Yan, Mingliang Jin, Xiangshen You, Shuting Xie, Zhenping Liu, Albert van den Berg, Jan C.T. Eijkel, Lingling Shui

Research output: Contribution to journalArticleAcademicpeer-review

1 Downloads (Pure)

Abstract

We report on a simple approach for in-channel functionalization of a polydimethylsiloxane (PDMS) surface to obtain a switchable and reversible wettability change between hydrophilic and hydrophobic states. The thermally responsive polymer, poly(N-Isopropylacrylamide) (PNIPAAm), was grafted on the surface of PDMS channels by UV-induced surface grafting. PNIPAAm-grafted PDMS (PNIPAAm-g-PDMS) surface wettability can be thermally tuned to obtain water contact angles varying in the range of 24.3 to 106.1° by varying temperature at 25-38 °C. By selectively modifying the functionalized area in the microfluidic channels, multiform emulsion droplets of oil-in-water (O/W), water-in-oil (W/O), oil-in-water-in-oil (O/W/O), and water-in-oil-in-water (W/O/W) could be created on-demand. Combining solid surface wettability and liquid-liquid interfacial properties, tunable generation of O/W and W/O droplet and stratified flows were enabled in the same microfluidic device with either different or the same two-phase fluidic systems, by properly heating/cooling thermal-responsive microfluidic channels and choosing suitable surfactants. Controllable creation of O/W/O and W/O/W droplets was also achieved in the same microfluidic device, by locally heating or cooling the droplet generation areas with integrated electric heaters to achieve opposite surface wettability. Hollow microcapsules were prepared using double emulsion droplets as templates in the microfluidic device with sequential hydrophobic and hydrophilic channel segments, demonstrating the strength of the proposed approach in practical applications.

Original languageEnglish
Pages (from-to)16934-16943
Number of pages10
JournalACS Applied Materials and Interfaces
Volume11
Issue number18
DOIs
Publication statusPublished - 8 May 2019

Fingerprint

Emulsions
Wetting
Oils
Water
Microfluidics
Polydimethylsiloxane
Cooling
Heating
Liquids
Fluidics
Surface-Active Agents
Contact angle
Capsules
Polymers
Surface active agents

Keywords

  • Droplet
  • Microcapsule
  • Microfluidics
  • Multi-emulsion
  • Reversible emulsion
  • Surface wettability
  • Thermoresponsive

Cite this

Li, Lanhui ; Yan, Zhibin ; Jin, Mingliang ; You, Xiangshen ; Xie, Shuting ; Liu, Zhenping ; van den Berg, Albert ; Eijkel, Jan C.T. ; Shui, Lingling. / In-Channel Responsive Surface Wettability for Reversible and Multiform Emulsion Droplet Preparation and Applications. In: ACS Applied Materials and Interfaces. 2019 ; Vol. 11, No. 18. pp. 16934-16943.
@article{455cdeb3431840ef979c0a50028890dd,
title = "In-Channel Responsive Surface Wettability for Reversible and Multiform Emulsion Droplet Preparation and Applications",
abstract = "We report on a simple approach for in-channel functionalization of a polydimethylsiloxane (PDMS) surface to obtain a switchable and reversible wettability change between hydrophilic and hydrophobic states. The thermally responsive polymer, poly(N-Isopropylacrylamide) (PNIPAAm), was grafted on the surface of PDMS channels by UV-induced surface grafting. PNIPAAm-grafted PDMS (PNIPAAm-g-PDMS) surface wettability can be thermally tuned to obtain water contact angles varying in the range of 24.3 to 106.1° by varying temperature at 25-38 °C. By selectively modifying the functionalized area in the microfluidic channels, multiform emulsion droplets of oil-in-water (O/W), water-in-oil (W/O), oil-in-water-in-oil (O/W/O), and water-in-oil-in-water (W/O/W) could be created on-demand. Combining solid surface wettability and liquid-liquid interfacial properties, tunable generation of O/W and W/O droplet and stratified flows were enabled in the same microfluidic device with either different or the same two-phase fluidic systems, by properly heating/cooling thermal-responsive microfluidic channels and choosing suitable surfactants. Controllable creation of O/W/O and W/O/W droplets was also achieved in the same microfluidic device, by locally heating or cooling the droplet generation areas with integrated electric heaters to achieve opposite surface wettability. Hollow microcapsules were prepared using double emulsion droplets as templates in the microfluidic device with sequential hydrophobic and hydrophilic channel segments, demonstrating the strength of the proposed approach in practical applications.",
keywords = "Droplet, Microcapsule, Microfluidics, Multi-emulsion, Reversible emulsion, Surface wettability, Thermoresponsive",
author = "Lanhui Li and Zhibin Yan and Mingliang Jin and Xiangshen You and Shuting Xie and Zhenping Liu and {van den Berg}, Albert and Eijkel, {Jan C.T.} and Lingling Shui",
year = "2019",
month = "5",
day = "8",
doi = "10.1021/acsami.9b03160",
language = "English",
volume = "11",
pages = "16934--16943",
journal = "ACS applied materials & interfaces",
issn = "1944-8244",
publisher = "American Chemical Society",
number = "18",

}

In-Channel Responsive Surface Wettability for Reversible and Multiform Emulsion Droplet Preparation and Applications. / Li, Lanhui; Yan, Zhibin; Jin, Mingliang; You, Xiangshen; Xie, Shuting; Liu, Zhenping; van den Berg, Albert; Eijkel, Jan C.T.; Shui, Lingling.

In: ACS Applied Materials and Interfaces, Vol. 11, No. 18, 08.05.2019, p. 16934-16943.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - In-Channel Responsive Surface Wettability for Reversible and Multiform Emulsion Droplet Preparation and Applications

AU - Li, Lanhui

AU - Yan, Zhibin

AU - Jin, Mingliang

AU - You, Xiangshen

AU - Xie, Shuting

AU - Liu, Zhenping

AU - van den Berg, Albert

AU - Eijkel, Jan C.T.

AU - Shui, Lingling

PY - 2019/5/8

Y1 - 2019/5/8

N2 - We report on a simple approach for in-channel functionalization of a polydimethylsiloxane (PDMS) surface to obtain a switchable and reversible wettability change between hydrophilic and hydrophobic states. The thermally responsive polymer, poly(N-Isopropylacrylamide) (PNIPAAm), was grafted on the surface of PDMS channels by UV-induced surface grafting. PNIPAAm-grafted PDMS (PNIPAAm-g-PDMS) surface wettability can be thermally tuned to obtain water contact angles varying in the range of 24.3 to 106.1° by varying temperature at 25-38 °C. By selectively modifying the functionalized area in the microfluidic channels, multiform emulsion droplets of oil-in-water (O/W), water-in-oil (W/O), oil-in-water-in-oil (O/W/O), and water-in-oil-in-water (W/O/W) could be created on-demand. Combining solid surface wettability and liquid-liquid interfacial properties, tunable generation of O/W and W/O droplet and stratified flows were enabled in the same microfluidic device with either different or the same two-phase fluidic systems, by properly heating/cooling thermal-responsive microfluidic channels and choosing suitable surfactants. Controllable creation of O/W/O and W/O/W droplets was also achieved in the same microfluidic device, by locally heating or cooling the droplet generation areas with integrated electric heaters to achieve opposite surface wettability. Hollow microcapsules were prepared using double emulsion droplets as templates in the microfluidic device with sequential hydrophobic and hydrophilic channel segments, demonstrating the strength of the proposed approach in practical applications.

AB - We report on a simple approach for in-channel functionalization of a polydimethylsiloxane (PDMS) surface to obtain a switchable and reversible wettability change between hydrophilic and hydrophobic states. The thermally responsive polymer, poly(N-Isopropylacrylamide) (PNIPAAm), was grafted on the surface of PDMS channels by UV-induced surface grafting. PNIPAAm-grafted PDMS (PNIPAAm-g-PDMS) surface wettability can be thermally tuned to obtain water contact angles varying in the range of 24.3 to 106.1° by varying temperature at 25-38 °C. By selectively modifying the functionalized area in the microfluidic channels, multiform emulsion droplets of oil-in-water (O/W), water-in-oil (W/O), oil-in-water-in-oil (O/W/O), and water-in-oil-in-water (W/O/W) could be created on-demand. Combining solid surface wettability and liquid-liquid interfacial properties, tunable generation of O/W and W/O droplet and stratified flows were enabled in the same microfluidic device with either different or the same two-phase fluidic systems, by properly heating/cooling thermal-responsive microfluidic channels and choosing suitable surfactants. Controllable creation of O/W/O and W/O/W droplets was also achieved in the same microfluidic device, by locally heating or cooling the droplet generation areas with integrated electric heaters to achieve opposite surface wettability. Hollow microcapsules were prepared using double emulsion droplets as templates in the microfluidic device with sequential hydrophobic and hydrophilic channel segments, demonstrating the strength of the proposed approach in practical applications.

KW - Droplet

KW - Microcapsule

KW - Microfluidics

KW - Multi-emulsion

KW - Reversible emulsion

KW - Surface wettability

KW - Thermoresponsive

UR - http://www.scopus.com/inward/record.url?scp=85065481158&partnerID=8YFLogxK

U2 - 10.1021/acsami.9b03160

DO - 10.1021/acsami.9b03160

M3 - Article

VL - 11

SP - 16934

EP - 16943

JO - ACS applied materials & interfaces

JF - ACS applied materials & interfaces

SN - 1944-8244

IS - 18

ER -