Capturing tensile size-dependency in polymer nanofiber elasticity.

Area of Science:

• Materials Science
• Nanotechnology
• Solid Mechanics

Background:

• Tensile size-dependency, the variation in material response under tension with size, differs significantly from bending size-dependency.
• Existing strain gradient elasticity models effectively predict bending size-dependency but fail to capture tensile size-dependency.
• Recent experimental evidence suggests the existence of tensile size-dependency, necessitating advanced modeling approaches.

Purpose of the Study:

• To develop a higher-order strain gradient elasticity model capable of predicting tensile size-dependency.
• To investigate and quantify the tensile size-dependency of polycaprolactone (PCL) nanofibers.

Main Methods:

• A higher-order strain gradient elasticity model was constructed by incorporating the second strain gradient into the deformation energy.
• Tensile experiments were conducted on 10 wt% polycaprolactone nanofibers to calibrate and validate the developed model.

Main Results:

• The study demonstrates that tensile size-dependency in the investigated PCL nanofibers becomes apparent at diameters of 600 nm and below.
• The characteristic length-scale parameter for these nanofibers was determined to be 1095.8 nm.
• The proposed higher-order model successfully captures the tensile size-dependent behavior.

Conclusions:

• The developed higher-order strain gradient elasticity model provides an accurate framework for understanding and predicting tensile size-dependency in nanofibers.
• This work validates the existence of tensile size-dependency in PCL nanofibers and quantifies its onset and characteristic length scale.
• The findings pave the way for more accurate mechanical modeling of nanomaterials under tensile loading.