Frictional resistance and delamination mechanisms in 2D tungsten diselenide revealed by multi-scale scratch andobservations.

Friction phenomena in two-dimensional (2D) materials are conventionally studied at atomic length scales in a few layers using low-load techniques. However, the advancement of 2D materials for semiconductor and electronic applications requires an understanding of friction and delamination at a few micrometers length scale and hundreds of layers. To bridge this gap, the present study investigates frictional resistance and delamination mechanisms in 2D tungsten diselenide (WSe) at 10m length and 100-500 nm depths using an integrated atomic force microscopy (AFM), high-load nanoscratch, andscanning electron microscopic (SEM) observations.

Quantum Dots on a String: In Situ Observation of Branching and Reinforcement Mechanism of Electrospun Fibers.

Immobilization of quantum dots (QDs) on fiber surfaces has emerged as a robust approach for preserving their functional characteristics while mitigating aggregation and instability issues. Despite the advancement, understanding the impacts of QDs on jet-fiber evolution during electrospinning, QDs-fiber interface, and composites functional behavior remains a knowledge gap. The study adopts a high-speed imaging methodology to capture the immobilization effects on the QDs-fiber matrix.

Direct Observation of Adhesion and Mechanical Behavior of a Single Poly(lactic--glycolic acid) (PLGA) Fiber Using an In Situ Technique for Tissue Engineering.

Nanometer- and submicrometer-sized fiber have been used as scaffolds for tissue engineering, because of their fundamental load-bearing properties in synergy with mechano-transduction. This study investigates a single biodegradable poly(lactic--glycolic acid) (PLGA) fiber's load-displacement behavior utilizing the nanoindentation technique coupled with a high-resolution in situ imaging system. It is demonstrated that a maximum force of ∼3 μN in the radial direction and displacement of at least 150% of fiber diameter should be applied to acquire the fiber's macroscopic mechanical properties for tissue engineering.