The polymer micro- or nano- fibers have been rapidly gaining popularity as a construction matrix for tissue engineering scaffolds.This paper presents a dynamic investigation of the poly(ε-caprolactone)(PCL) sub-micro fibers with diameters ranging from 100 nm to 500 nm by electrospinning method.To obtain the dynamic properties

the fiber was placed on a surface which had a groove of 100 μm width

and the experiments using a functional generator and piezo-tablet were conducted on a vibrating single-strand fiber.The amplitude and driving frequency can be observed by using the ultra-high optical microscope and functional generator respectively.Additionally

since the dynamic property is highly sensitive to the fiber diameter

and real fibers have an ellipsoidal cross-section

it is necessary to correct the experimental data.The equal diameter is defined and the value can be measured by using the AFM equipment.The elastic modulus can be obtained when the PCL fiber beam arrived at its first resonant frequency.Our measurements show that its elastic modulus exhibits an inverse size dependency with the fiber diameter.The elastic modulus of the fiber increased obviously when its diameter was reduced past a threshold size.A dynamics-based strain gradient model was presented to correlate with the experimental data

and it appeared to explain the phenomenon quite accurately.