Primary surface measurement reported
Water contact angle measurements on Parafilm® surfaces (before vs. after laser ablation of the paper).
Client Citation Analysis
Engineered detection zone to enhance color uniformity on paper microfluidics fabricated via Parafilm®-heating-laser-cutting
This study presents a Parafilm®-laminated paper microfluidics fabrication workflow and engineered detection zones that improve the color uniformity of a glucose assay, and uses water contact-angle measurements to evaluate whether the laser ablation step affects Parafilm® hydrophobicity.
At-a-Glance Summary
Dropometer attribution in the paper
Water contact angle was assessed using Dropometer (Droplet Lab) in the device characterization methods.
How the contact-angle data were used in the study
The contact-angle comparison was used to investigate whether laser ablation of the paper alters the hydrophobicity of the Parafilm® layer used in the fabrication method, with results presented as a before/after comparison.
Replication / reliability statement
Figure 3A reports contact-angle values with (n = 3).
Paper Details
Title
Engineered detection zone to enhance color uniformity on paper microfluidics fabricated via Parafilm®-heating-laser-cutting
Authors
Seyed Hamid Safiabadi Tali; Hasti Hajimiri; Zubi Sadiq; Sana Jahanshahi-Anbuhi
Journal
Sensors and Actuators: B. Chemical
Year
2023
Volume
380
Pages / Article
133324
15.6
Scopus metrics (Elsevier / Scopus rating 2024)
Scopus metrics (Elsevier / Scopus rating 2024)
CiteScore subject ranks (CiteScore 2024)
- Q1 — Physics and Astronomy: Instrumentation (4/174)
- Q1 — Chemistry: Analytical Chemistry (6/160)
1.332
Scopus metrics (Elsevier / Scopus rating 2024)
1.509
Scopus metrics (Elsevier / Scopus rating 2024)
7.7
Journal Impact Factor (Clarivate JCR)
Journal Impact Factor (Clarivate JCR)
5-Year Impact Factor
Journal Impact Factor (Clarivate JCR)
JCR category rank
What Was Measured
Primary surface / interfacial measurement
Water contact angle of (i) a pristine Parafilm® sheet and (ii) the Parafilm® layer after laser ablation of the paper.
Supporting measurements
Device characterization included laminated-paper thickness measurements, optical microscopy of the cross-sectional structure, and image/video-based measurements (with ImageJ) of barrier/channel widths and flow speed using dye solutions in HPLC water. Relative humidity and temperature were recorded during flow-speed measurements.
Water contact angle
Dropometer (Droplet Lab)
Thickness
Micrometer (Mitutoyo, Cat. No. 293–832–30)
Laser ablation
CO₂ laser cutter (Universal Laser Systems, VLS 2.30DT with a 2.0 lens)
Cross-sectional imaging
Optical microscope (Westover Scientific)
Width/flow image analysis
ImageJ
Humidity & temperature logging
Thermo-hygrometer (Govee Inc.)
Data analysis
MS Excel 2019
Lamination heating
Laboratory oven (Thermo Scientific, Cat. No. 11-475-152)
Role of the Dropometer
The authors used Dropometer (Droplet Lab) to measure water contact angle on Parafilm® surfaces as a before/after comparison: a pristine Parafilm® sheet versus the Parafilm® layer following laser ablation of the paper from Parafilm®-laminated paper. For the post-ablation measurement, a 2.5 × 2.5 cm paper area was completely ablated, and the contact angle was measured on the exposed Parafilm® layer.
In the paper’s workflow, this Dropometer-based comparison supports the fabrication discussion by checking whether the laser ablation step used in the PHLC process affects Parafilm® hydrophobicity.
Bring This Measurement Into Your Lab
If you need water contact angle checks on laminated or laser processed films, we can show you the same contact angle workflow on your samples.
Key Findings
Before/after hydrophobicity comparison
Water contact angle was measured on a pristine Parafilm® sheet and on the Parafilm® layer after laser ablation of the paper to evaluate whether the ablation step affects Parafilm® hydrophobicity.
Nearly identical contact-angle values
The reported contact angles were 108 ± 5° (pristine Parafilm®) and 109 ± 5° (Parafilm® after laser ablation of the paper), presented in Figure 3A.
Interpreted as minimal wettability change under the chosen laser settings
The authors discuss that laser ablation may alter surface roughness and wettability depending on settings and material, and they suggest the observed similarity in wettability is possibly due to using laser settings intended to cut the paper with minimal impacts on Parafilm®.
Dropometer measurement integrated into device characterization
In the characterization section, the Dropometer-based contact-angle measurement appears alongside thickness measurements, optical microscopy, and channel/barrier characterization used to describe the fabricated µPAD structure and dimensions.
Figures & Visuals
What it shows
Side-by-side contact-angle images and values comparing unmodified Parafilm® versus Parafilm® after laser cutting/ablation of the paper (reported with n = 3).
What it shows
Top-view and cross-sectional microscopic images illustrating the laminated device structure and the hydrophobic barrier / hydrophilic channel geometry that accompanies the contact-angle characterization.
What it shows
A schematic of the PHLC process showing lamination by oven heating followed by CO₂ laser ablation of patterns on the paper side.
Why It Matters
Parafilm® serves as the hydrophobic component in the paper-lamination approach used to fabricate the µPADs in this study. The Dropometer-based water contact-angle measurements provide a direct check on Parafilm® wettability before and after the laser ablation step that patterns the paper side.
Within the authors’ fabrication discussion, the contact-angle comparison supports their assessment of how the chosen laser-ablation settings interact with the laminated Parafilm® layer during device fabrication.
Expert Perspective
Practical Takeaways
Use a before/after contact-angle check for laser-processing steps
The study measures water contact angle on pristine Parafilm® and after paper laser ablation to assess how the ablation step relates to Parafilm® hydrophobicity.
Match the “after” surface to the processed region
The post-ablation contact angle is measured on the Parafilm® layer exposed by completely ablating a 2.5 × 2.5 cm paper area from the laminated substrate.
Report the contact-angle values alongside the fabrication context
The paper presents the contact-angle comparison in Figure 3A as part of the device characterization narrative around the PHLC fabrication workflow.
Include replication for the contact-angle comparison
Figure 3A reports the contact-angle values with (n = 3).
Frequently Asked Questions
What did the Dropometer measure in this study?
The authors used a Dropometer (Droplet Lab) to measure the water contact angle of a pristine Parafilm® sheet and of the Parafilm® layer exposed after laser ablation of the paper. For the second measurement, a 2.5 × 2.5 cm area of paper was completely ablated from the Parafilm® laminated paper before the angle was measured on the exposed Parafilm®.
What contact angle values were reported?
The paper reports a water contact angle of 108 ± 5° for pristine Parafilm® and 109 ± 5° for Parafilm® after laser ablation of the paper, with n = 3 (Fig. 3A). The authors conclude that the hydrophobicity of Parafilm® after ablation was similar to that of the pristine sheet.
What does the result mean for the fabrication method?
The authors suggest the wettability of Parafilm® did not significantly change, possibly because the laser settings were chosen to cut the paper with minimal impact on the Parafilm®. They note that laser ablation can alter surface roughness and wettability depending on the settings and material, so the result applies to the conditions used in this study; surface roughness itself was not measured in the paper.