English to Japanese Other Physics

The surface tension or surface energy describes the energy cost per unit area of producing new interface and is related to the intermolecular forces that hold materials together.
又は
The stronger the intermolecular bonding in the material, the greater the energy cost of producing new surface and higher the surface tension.

上記の二つの文に出てくる｢material｣をどのように訳せばよいか教えてください。　よろしくお願いします。