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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

Primary surface measurement reported

Water contact angles (sessile DI water drops) on blade-cast elastomer films.

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 XXXX, XXX, XXX−XXX
DOI
10.1021/acs.macromol.5c01696

Journal context

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Scopus metrics (Elsevier / Scopus rating 2024)

CiteScore 2024

9.0

SNIP 2024

1.222

SJR 2024

1.352

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)

Journal Impact Factor (Clarivate JCR)

Journal Impact Factor (JCR 2025)

5.2

5-Year Impact Factor

5.2

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.

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).

Method Snapshot

Method Snapshot Table

Sample / spacer series (as reported) Spacer chemistry context (as described) Spacer graft ratio(s) reported Surface output Instruments Conditions (as stated) Notes / figure
TES-1 Contains neither fluorine nor nitrogen — Water contact angle Droplet Lab Dropometer; Droplet Lab’s Sessile software (“smart mode”) ~0.1 g blade-cast on glass slides; ~100 µm film thickness; ~5 µL DI water droplet Used as the “no fluorine” reference in Figure 4c
DMFS-3, DMFS-2, DMFS-1 Fluorine-containing spacer (DMFS) 0.32%, 0.79%, 1.56% (fluorine grafting ratios) Water contact angle Droplet Lab Dropometer; Droplet Lab’s Sessile software (“smart mode”) ~0.1 g blade-cast on glass slides; ~100 µm film thickness; ~5 µL DI water droplet; five measurements per sample Contact angles reported vs increasing graft ratios (Figure 4c)
TMAS-3, TMAS-2, TMAS-1 Nitrogen-containing spacer (TMAS) 0.32%, 0.79%, 1.56% Water contact angle Droplet Lab Dropometer; Droplet Lab’s Sessile software (“smart mode”) ~0.1 g blade-cast on glass slides; ~100 µm film thickness; ~5 µL DI water droplet Contact angles reported vs increasing graft ratios (Figure 4c)

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

Figure 4c — Contact angle vs graft ratio for fluorine- and nitrogen-containing spacers

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.

Figure 4b — Surface-behavior visual tied to spacer-driven wettability changes

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).

Figure 4a — Spacer effects summarized across multiple property axes

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.

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.

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