Quantitative Conductive Atomic Force Microscopy on Single-Walled Carbon Nanotube-Based Polymer Composites

Area of Science:

• Materials Science
• Nanotechnology
• Electrical Engineering

Background:

• Conductive atomic force microscopy (C-AFM) is crucial for correlating electrical properties with topography in polymer composites.
• Quantifying C-AFM results is challenging due to tip-sample interactions, environmental factors, and tip degradation.

Purpose of the Study:

• To determine optimal C-AFM conditions for reliable, quantitative current mapping of single-walled carbon nanotube (SWCNT) networks.
• To calculate point-by-point resistance in polymer-impregnated and non-impregnated SWCNT networks.

Main Methods:

• Utilized conductive atomic force microscopy (C-AFM) to analyze SWCNT networks.
• Investigated C-AFM performance on macroscale samples and thin composite sections (150-350 nm).
• Focused on tip-sample contact resistance and its impact on measurements.

Main Results:

• Macroscale C-AFM measurements were limited by tip-sample contact resistance, preventing distinction of sample resistance.
• Quantitative C-AFM on thin sections allowed separation of sample and contact resistance but lacked representativeness.
• Successfully characterized local electrical properties, including homogeneity and resistance of SWCNT clusters at nano- and microscales.

Conclusions:

• C-AFM requires careful condition optimization for accurate electrical property assessment in polymer composites.
• While macroscale measurements are limited, C-AFM effectively characterizes local electrical behavior and homogeneity at smaller scales.
• Thin sample sections offer improved resistance quantification but may not represent the bulk material.