Primary surface measurement reported
Water contact angles (sessile DI water drops) on blade-cast elastomer films.
Client Citation Analysis
UV Responsive, Bottlebrush Structured Silicone Elastomers: Synthesis, Healing, and Application
This paper reports UV-responsive bottlebrush silicone elastomers and uses sessile-drop water contact angle measurements to quantify how spacer graft chemistry (fluorine vs nitrogen) changes surface wettability.
At-a-Glance Summary
Dropometer attribution in the paper
The paper states that “the shape of the droplet was captured by using the Droplet Lab Dropometer,” with contact angles determined in “smart mode” in Droplet Lab’s Sessile software using Young–Laplace and polynomial methods.
How the surface-tension / contact-angle data were used in the study
Water contact angles were reported for TES-1 and spacer-grafted samples (DMFS and TMAS series) as a function of graft ratio to compare fluorine- and nitrogen-containing spacers and interpret changes in surface hydrophilicity/hydrophobicity (Figure 4c).
Replication / reliability statement
For each sample, a total of five measurements were conducted.
Paper Details
Title
UV Responsive, Bottlebrush Structured Silicone Elastomers: Synthesis, Healing, and Application
Authors
Miao Huo; David R. Clarke
Journal
Macromolecules
Year
2025
Pages / Article
Macromolecules 2025, 58 (19), 10490–10498
9.0
Scopus metrics (Elsevier / Scopus rating 2024)
1.222
Scopus metrics (Elsevier / Scopus rating 2024)
1.352
Scopus metrics (Elsevier / Scopus rating 2024)
CiteScore subject ranks (CiteScore 2024)
- Q1 - Chemistry - Organic Chemistry (20/212)
- Q1 - Materials Science - Polymers and Plastics (28/167)
- Q1 - Chemistry - Inorganic Chemistry (11/81)
- Q1 - Materials Science - Materials Chemistry (58/324)
5.2
Journal Impact Factor (Clarivate JCR)
5.2
Journal Impact Factor (Clarivate JCR)
What Was Measured
Primary surface / interfacial measurement
Water contact angles were measured using sessile DI water droplets on elastomer films prepared by blade-casting on glass slides.
Supporting measurements
The study reports rheological testing under UV illumination, tensile testing, NMR measurements, FTIR measurements, and GPC testing, alongside demonstrations of UV forming/healing and 3D printing.
Contact angle
Droplet Lab Dropometer; Droplet Lab’s Sessile software (“smart mode”)
Rheology (parallel plate, with UV illumination)
TA HR 20 discovery hybrid rheometer; Omnicure S2000 spot UV curing system
Tensile testing
Tension geometry attachment to the TA HR 20 discovery hybrid rheometer
NMR
JEOL ECZ400S 400 MHz spectrometer
FTIR (ATR)
Thermo Fisher Scientific Nicolet iS-50 FT-IR spectrometer with diamond attenuated total reflection (ATR)
GPC
Agilent 1260 Infinity system (refractive index detector)
3D printing
Anycubic Mono 4 DLP printer
Mixing
Thinky mixer
Role of the Dropometer
A droplet (~5 µL) of deionized (DI) water was applied to blade-cast elastomer films (~100 µm thick), and the droplet shape was captured by using the Droplet Lab Dropometer to obtain water contact angles. Contact angles were determined in “smart mode” in Droplet Lab’s Sessile software, which the authors state employs both Young–Laplace and polynomial methods for calculation.
In the Results section, the contact-angle measurements are used to compare how fluorine- and nitrogen-containing spacer grafts shift surface hydrophobicity/hydrophilicity as a function of graft ratio (Figure 4c).
Bring This Measurement Into Your Lab
If you are tuning water contact angle on silicone elastomer films through surface chemistry, we can show you the same sessile drop workflow.
Key Findings
Fluorinated spacer grafting increases water contact angle
The paper reports that “the water contact angle increases with increasing fluorine content.” When no fluorine is present, the contact angle is 98.4°, and incorporation of 0.32% fluorine raises it to 118°.
Higher fluorine graft ratio corresponds to higher reported contact angle
At a graft ratio of 1.56% (fluorine case), the reported water contact angle increases to 125°.
Nitrogen-containing TMAS grafting shifts contact angle in the opposite direction
The paper reports that water contact angle decreases with increasing nitrogen content, with incorporation of 1.56% TMAS resulting in a decrease of approximately 10° in contact angle (described as a slight increase in surface hydrophilicity).
Spacer identity is presented as a surface-property design lever
The authors state that incorporating different spacers demonstrates a clear structure–property relationship, and the contact-angle results are part of the evidence that spacers can serve as a modular design element for property tuning.
Figures & Visuals
What it shows
Plots water contact angles for TES-1, DMFS-1/2/3, and TMAS-1/2/3 as graft ratios increase, showing opposite-direction trends for fluorine vs nitrogen spacer series.
What it shows
Shows images of milk droplets rolling on TES-1 and DMFS-1 surfaces, illustrating a difference in surface behavior (including traces and shadows noted in the caption).
What it shows
Provides a visual summary of how functional spacers relate to reported responsive material properties, including the surface-property change associated with fluorinated spacers.
Why It Matters
The study’s spacer-grafting strategy is presented as a way to tune bottlebrush elastomer properties by attaching small silane molecules as spacers on the polymer backbone. Within that framework, the water contact-angle measurements provide a direct surface-property readout showing how fluorine- and nitrogen-containing spacers shift hydrophobicity/hydrophilicity.
In the paper’s discussion, these contact-angle trends support a structure–property relationship argument: small changes in spacer chemistry and graft ratio correspond to measurable, directional changes in surface wettability, alongside the broader UV-responsive forming/healing behavior reported for the elastomer system.
Expert Perspective
Practical Takeaways
Dropometer-based sessile contact angle workflow (as used in the paper)
Blade-cast films (~100 µm) were tested with ~5 µL DI water droplets, with droplet shape captured by using the Droplet Lab Dropometer and contact angles computed in Droplet Lab’s Sessile software (“smart mode”).
Fluorinated spacer DMFS drives higher reported contact angles
The paper reports a change from 98.4° (no fluorine) to 118° at 0.32% fluorine, and up to 125° at a 1.56% graft ratio (fluorine case).
Amine-containing TMAS shifts contact angle downward at comparable graft ratio
At 1.56% TMAS, the paper reports an approximately 10° decrease in contact angle, interpreted as a slight increase in surface hydrophilicity.
Contact angle is used as a spacer-selection comparator
The paper uses contact-angle vs graft-ratio comparisons (Figure 4c) to distinguish fluorine- vs nitrogen-containing spacer effects on surface wettability within the broader elastomer design space.
Frequently Asked Questions
What did the Dropometer measure in this study?
The Methods describe water contact angle measurements on the fluorinated spacer samples DMFS-1, DMFS-2 and DMFS-3, cast as films about 100 µm thick on glass slides. A droplet of about 5 µL of deionized water was imaged with the Droplet Lab Dropometer, contact angles were determined in smart mode in Droplet Lab's Sessile software, and five measurements were made per sample.
What contact angle values were reported?
The authors report 98.4° with no fluorine present, 118° at a 0.32% fluorine graft ratio and 125° at a 1.56% graft ratio. Grafting 1.56% of the nitrogen containing spacer TMAS lowered the contact angle by approximately 10° (Figure 4c).
What do the results mean for the elastomer design?
The authors report that the water contact angle rises with fluorine content and falls with nitrogen content, and note that even a low fluorine content had a substantial impact on surface hydrophobicity. They present this as a clear relationship between structure and properties, suggesting spacers can serve as a modular design element for tuning both bulk and interfacial properties.