Primary surface measurement reported
The study reports water contact angle (WCA) on the optimized corncob cellulosic residue (CCR) film as a wettability indicator.
Client Citation Analysis
Corncob-Derived Biodegradable Packaging Films: A Sustainable Solution for Raspberry Post-harvest Preservation
This study develops corncob-derived biodegradable packaging films for raspberry post-harvest preservation and reports water contact angle (WCA) measurements to characterize film wettability within the film’s hydration-property evaluation.
At-a-Glance Summary
Dropometer attribution in the paper
WCA is measured using a “0.05 µL precise dropper from the Dropometer (Droplet Lab)”, with a smartphone image analyzed in sessile drop software to calculate the contact angle.
How the contact-angle data were used in the study
The WCA output is used to classify the CCR film as hydrophilic based on the authors’ stated <90° wettability criterion, and to motivate discussion of hydrophobicity targets for food packaging.
Replication / reliability statement
Three sample measurements were used to calculate the average WCA value.
Paper Details
Title
Corncob-Derived Biodegradable Packaging Films: A Sustainable Solution for Raspberry Post-harvest Preservation
Authors
Sandeep Paudel; Srinivas Janaswamy
Journal
Food Chemistry
Year
2024
Volume
454
Pages / Article
139749
License
Elsevier user license 1.0
18.3
Scopus metrics (Elsevier / Scopus rating 2024)
Scopus metrics (Elsevier / Scopus rating 2024)
CiteScore subject ranks (CiteScore 2024)
- Q1 - Chemistry - Analytical Chemistry (3/160)
- Q1 - Agricultural and Biological Sciences - Food Science (10/404)
2.153
Scopus metrics (Elsevier / Scopus rating 2024)
1.952
Scopus metrics (Elsevier / Scopus rating 2024)
9.8
Journal Impact Factor (Clarivate JCR)
What Was Measured
Primary surface / interfacial measurement
Water contact angle (WCA, in degrees) was measured on the optimized CCR film using a sessile-drop approach with image-based analysis.
Supporting measurements
The study also reports film performance and characterization measurements including water vapor permeability (WVP), tensile strength (TS) and elongation at break (EB), hydration-property tests (e.g., water absorption behavior), and spectroscopic characterization (UV–Vis transmittance and FTIR).
Water contact angle
0.05 µL precise dropper from the Dropometer (Droplet Lab) (smartphone picture; sessile drop software)
Tensile strength / elongation at break
Texture Analyzer of Stable Micro Systems (Model TA-HD plus; serial no: 5529)
UV–Vis transmittance
UV-Vis spectrophotometer (VWR International, Model no: UV-1600PC, 10037-436)
FTIR spectra
FTIR spectrophotometer (PerkinElmer, Spectrum 100)
Color
Nix Pro 2 color sensor
Film thickness
digital micrometer vernier caliper
Non-cellulosic/total sugar analysis and glycosyl linkage analysis
gas chromatography-mass spectrometry (GC-MS)
Molecular weight determination
diffusion-ordered spectroscopy nuclear magnetic resonance
Role of the Dropometer
The authors measure water contact angle by placing the film sample on the mount, dispensing a water droplet using a “0.05 µL precise dropper from the Dropometer (Droplet Lab)”, capturing a smartphone picture of the droplet, and analyzing the image using sessile drop software to calculate WCA (protocol cited to Chen et al., 2018). The reported WCA value is based on three measurements averaged.
In the results discussion, the WCA output is used as a wettability classifier (hydrophilic vs hydrophobic) for the optimized CCR packaging film and is discussed in the context of hydrophobicity targets for food packaging.
Bring This Measurement Into Your Lab
If you need water contact angle on biodegradable packaging films, we can show you the same sessile drop workflow on your own film samples.
Key Findings
Dropometer-based WCA workflow is explicitly described
The methods specify a sessile-drop WCA workflow using a 0.05 µL Dropometer dropper, smartphone imaging, and sessile drop software to calculate contact angle.
Optimized CCR film shows a WCA of 63.4°
In the WCA results section, the CCR film is reported to display a contact angle of 63.4°, with the value linked to Fig. 4c.
WCA is used to place the film in the authors’ hydrophilicity regime
The authors state that angles less than 90° denote hydrophilicity and use the measured WCA to stress the film’s hydrophilic character.
Hydrophobicity is framed as a food-packaging goal in the discussion
The paper notes that hydrophobic packaging films are generally desired for food packaging and discusses additive approaches reported in prior work as strategies to improve WCA.
Figures & Visuals
What it shows
Panel (c) presents the water contact angle measurement image associated with the optimized CCR film.
What it shows
Figure 4 groups the water absorption, water contact angle and soil biodegradation results and includes the WCA measurement as panel (c), which is referenced directly in the WCA discussion.
Why It Matters
Within this work, WCA is treated as a core wettability parameter for packaging films, used to distinguish hydrophilic versus hydrophobic surface behavior using a stated 90° criterion. The sessile-drop measurement made with the Dropometer dropper provides the paper’s quantitative wettability value for the optimized CCR film.
In the results discussion, the authors connect the measured WCA to hydrophilicity classification and use it to frame hydrophobicity as a desirable target for food-packaging materials, motivating further exploration of approaches to improve CCR film hydrophobicity.
Expert Perspective
Practical Takeaways
Exact Dropometer credit line used by the authors
The WCA method attributes droplet dispensing to a “0.05 µL precise dropper from the Dropometer (Droplet Lab)”, paired with smartphone imaging and sessile drop software analysis.
Low-volume sessile-drop WCA setup
The procedure is described as mounting the film, placing a water droplet, capturing a smartphone image, and calculating WCA from the droplet image.
Triplicate averaging for the reported WCA
The reported WCA value is an average of three measurements.
WCA used as a hydrophilicity classifier
The CCR film’s WCA (63.4°) is interpreted using the paper’s <90° hydrophilicity criterion.
Where the Dropometer-derived output appears
The WCA visualization is presented in Fig. 4c, which is cited directly in the WCA results text.
Frequently Asked Questions
What did the Dropometer do in this study?
The authors measured water contact angle (WCA) on the optimized corncob cellulosic residue (CCR) film, dispensing the water droplet with the 0.05 μL precise dropper from the Dropometer (Droplet Lab). A smartphone picture of the drop was analysed in sessile drop software, and the reported value is the average of three measurements.
What contact angle did the film show, and how did the authors interpret it?
The CCR film displayed a water contact angle of 63.4° (Fig. 4c). Using the criterion that angles below 90° indicate hydrophilicity, the authors describe the film as hydrophilic, in line with values reported for other biodegradable films such as cellulose, chitosan and starch.
What does the paper leave open on film wettability?
The authors note that hydrophobic films are generally desired for food packaging and suggest that additives to raise the WCA of CCR films need to be researched. The study reports WCA for the optimized film only, so the effect of additives or other formulations on contact angle was not measured here.