Ligand graft functionalized substrates

An article comprising a porous thermoplastic substrate and extending from the surfaces thereof free-radically grafted biguanide ligand groups to form a free-radically-grafted substrate, wherein the free-radically grafted substrate is of the formula:

• Substrate˜(Mligand)m, where Substrate represents the thermoplastic substrate, Mligand represents a polymerized grafted ethylenically unsaturated monomer having pendant biguanide ligand groups, and m is at least two;
• wherein said pendent biguanide ligands groups are selected from one or more of the formula:
• wherein
• R2 is an arylene or alkylene and a is at least one and wherein the grafted ligand groups comprise the reaction product of a free-radically grafted electrophilic functional group and a ligand compound:
• wherein
• each R4 is individually H, alkyl or aryl,
• each R6 is individually alkylene or arylene,
• c may be zero or an integer from 1 to 500, and
• d is zero or 1, with the proviso that when d is zero, then c is 1 to 500.