Void closure and interdiffusion processes during latex film formation from surfactant-free polystyrene particles: a...

Area of Science:

• Polymer Science
• Materials Science
• Physical Chemistry

Background:

• Film formation from latex particles is crucial for material properties.
• Understanding the kinetics of film formation requires precise monitoring techniques.
• Surfactant-free latex systems present unique challenges and opportunities in film development.

Purpose of the Study:

• To develop and validate a steady-state fluorescence (SSF) technique for studying film formation in surfactant-free polystyrene (PS) latex.
• To monitor and quantify the stages of film formation, including onset, void closure, and healing, during thermal annealing.
• To determine the activation energies associated with these film formation processes.

Main Methods:

• Preparation of pyrene (P)-labeled PS latex films.
• Annealing films at elevated temperatures above the glass transition (T(g)) temperature for various time intervals.
• Monitoring film transparency using photon transmission intensity (I(tr)).
• Measuring scattered light (I(sc)) and fluorescence intensity (I(0P)) to track film evolution.
• Utilizing Scanning Electron Microscopy (SEM) for structural analysis.

Main Results:

• Demonstrated the effectiveness of SSF in tracking film formation stages.
• Identified onset temperature (T(0)), void closure temperature (T(v)), and healing temperature (T(h)).
• Quantified activation energies for void closure and interdiffusion stages.
• Observed significant changes in film transparency and physical structure upon annealing.

Conclusions:

• The SSF technique provides a sensitive method for studying latex film formation.
• Kinetic parameters and activation energies offer insights into the underlying physical processes.
• The findings contribute to understanding and controlling the formation of high-quality polymer films.