Contact angle a contact angle of 0°. This is often the case for water on bare metallic or ceramic surfaces, although the presence of an oxide layer or contaminants on the solid surface can significantly increase the contact angle. Generally, if the water contact angle is smaller than 90°, the solid surface is considered hydrophilic and if the water contact angle is larger than 90°, the solid surface is considered hydrophobic. Many polymers exhibit hydrophobic surfaces. Highly hydrophobic surfaces made of low surface energy (e.g. fluorinated) materials may have water contact angles as high as ~120°. Some materials with highly rough surfaces
Less-than sign encoded as a single-byte code point token. In Fortran, operator .LE. means "less than or equal to". In Bourne shell and Windows PowerShell, the operator -le means "less than or equal to". In the R programming language, the less-than sign is used in conjunction with a hyphen-minus to create an arrow (codice_1), this can be used as the left assignment operator. In Bourne shell (and many other shells), less-than sign is used to redirect input from a file. Less-than plus ampersand (<&) is used to redirect from a file descriptor. Less-than sign is used in the spaceship operator. In HTML