8.3 REACTIVITY: MOLECULAR INTERACTIONS 8.3.1 Surface Modifying/Degradative Interactions: Effects of the body on the biomaterial 8.3.1.1 Water 8.3.1. 1.1 Absorption(e.g, high water absorption by hydrogels is desired but even low water absorption by thermoplastics polymers can adversely affect mechanical properties 8.3. 1.1.2 Hydrolysis(.g, of ester linkage of polymers) 8.3.1.1. 3 Water as electrolyte solution facilitates corrosion of metal 8.3. 1 1.4 Dissolution of certain substances (e. g, calcium phosphates 8.3.1.2 Oxygen 8.3.1.2. 1 Oxide formation(e.g, on metals) 8.3. 1.2.2 Oxidative degradation of polymers 8.3. 1.2.3 Corrosion of metal(e. g, sites of depleted oxygen undergo anodic reaction) 8.3.1.3 Cations and Anions Contributing to Corrosion, Dissolution, and Precipitation (e.g, mineralization/calcification 8.3. 1.4 Enzymes(e.g, enzymolysis of natural polymers such as collagen) Macromolecule Absorption(e.g, lipid absorption) 8.3.2 Molecular interactions with biological molecules: Effects of the biomaterial on the 8.3.2.1 Water 8.3.2. 1 1 Hydrophobic interactions 8.3.2.2 Charge Interactions 8.3.2.2. 1 lonic(primary bonding) 8.3.2.2.2 Secondary 8.3.2.2.2. 1 Hydrogen bonding 8.3.2.2.2.2 Van der Waals interactions8.3 REACTIVITY: MOLECULAR INTERACTIONS 8.3.1 Surface Modifying/Degradative Interactions: Effects of the Body on the Biomaterial 8.3.1.1 Water 8.3.1.1.1 Absorption (e.g., high water absorption by hydrogels is desired but even low water absorption by thermoplastics polymers can adversely affect mechanical properties) 8.3.1.1.2 Hydrolysis (e.g., of ester linkage of polymers) 8.3.1.1.3 Water as electrolyte solution facilitates corrosion of metal 8.3.1.1.4 Dissolution of certain substances (e.g., calcium phosphates) 8.3.1.2 Oxygen 8.3.1.2.1 Oxide formation (e.g., on metals) 8.3.1.2.2 Oxidative degradation of polymers 8.3.1.2.3 Corrosion of metal (e.g., sites of depleted oxygen undergo anodic, reduction, reaction) 8.3.1.3 Cations and Anions Contributing to Corrosion, Dissolution, and Precipitation (e.g., mineralization/calcification) 8.3.1.4 Enzymes (e.g., enzymolysis of natural polymers such as collagen) Macromolecule Absorption (e.g., lipid absorption) 8.3.2 Molecular Interactions with Biological Molecules: Effects of the Biomaterial on the Body 8.3.2.1 Water 8.3.2.1.1 Hydrophobic interactions 8.3.2.2 Charge Interactions 8.3.2.2.1 Ionic (primary bonding) 8.3.2.2.2 Secondary 8.3.2.2.2.1 Hydrogen bonding 8.3.2.2.2.2 Van der Waals interactions