6750 J Mater sci(2008)43:6747-6757 self-repairable. In addition, the discrete molecular nature of Micro-scale interphase the"interphases"between various length scales in hard tissues result in mechanically stiff and tough natural The research of the micro-scale interphase phenomena in composites [12, 13 composite materials has attracted considerable attention of Q. In this paper, the interphase phenomena in the manmade both the scientific and engineering communities over the and natural polymer matrix composite structures at the last 50 years. Good succes has been achieved in describing micro-and nano-scales are briefly reviewed. The bridging the role of the interphase in stress transfer from the matrix laws for transformation of properties of the discrete matter at to the fiber using model single fiber composites(Fig. 4) the nano-scale to the continuum matter at the micro-scale From the simple Kelly-Tyson model, to the various lap based on the combination of gradient strain elasticity and shear models, to the numerical F E.A. models, the approach reptation dynamics of a chain above Tg, will also be outlined. based on the continuum mechanics has been employed interphase considering only the (a) Fig 4(a) Visualizing the Bulk polymer Interphase Stress transfer micro-scale. Interphase is a ontinuum layer with a gradient 50 um Diffuse interfa Fiber/inclusion in its structure. The main role of the micro-scale interphase is to provide stable and effective means for stress transfer between inclusions and polyn matrix even under adverse 10 um Sharp interface structure of a micro-composite onside i Property gradient discrete structure of the matrix Filler adhesion and inclusions becomes evident uter 0000050.10 015020 Normalized Distance Micro-scale Nano-scale Polymer matriⅸx Micro-scale interphase ber/inclusion Nano-scale 2 Springerself-repairable. In addition, the discrete molecular nature of the ‘‘interphases’’ between various length scales in hard tissues result in mechanically stiff and tough natural composites [12, 13]. In this paper, the interphase phenomena in the manmade and natural polymer matrix composite structures at the micro- and nano-scales are briefly reviewed. The bridging laws for transformation of properties of the discrete matter at the nano-scale to the continuum matter at the micro-scale, based on the combination of gradient strain elasticity and reptation dynamics of a chain above Tg, will also be outlined. Micro-scale interphase The research of the micro-scale interphase phenomena in composite materials has attracted considerable attention of both the scientific and engineering communities over the last 50 years. Good succes has been achieved in describing the role of the interphase in stress transfer from the matrix to the fiber using model single fiber composites (Fig. 4). From the simple Kelly-Tyson model, to the various lap shear models, to the numerical F.E.A. models, the approach based on the continuum mechanics has been employed Fig. 4 (a) Visualizing the interphase considering only the micro-scale. Interphase is a continuum layer with a gradient properties reflecting variations in its structure. The main role of the micro-scale interphase is to provide stable and effective means for stress transfer between inclusions and polymer matrix even under adverse conditions. (b) Visualizing the structure of a micro-composite considering also the nano-scale structural features when the discrete structure of the matrix and inclusions becomes evident 6750 J Mater Sci (2008) 43:6747–6757 123