Lubricating Polymer Surfaces

FROM THE PREFACE The surface modification of polymeric materials has been the object of a large number of investigations, but little attention has been paid to making a polymer surface frictionless or slippery, and lubricating surfaces are practically unmentioned in any books so far published, probably because of the relatively minor importance of polymer friction in industrial applications. A lubricating polymer surface is important, especially in marine and biomedical technologies. For instance, biomaterials to be used for catheterization on the urinary, tracheal, and cardiovascular tracts, or for endoscopy, should have a surface with good handling characteristics when dry and which preferably becomes slippery upon contact with body liquids. Such a low-friction surface must enable easy insertion and removal of the device from a patient. It would further prevent mechanical injury to the mucous membranes and minimize discomfort to the patient. Earlier approaches to providing a low-friction surface were mostly simple applications involving lubricants such as lidocaine jelly, silicone oil, or non-permanent coating with low-friction materials such as polyethylene or fluoroplastics. However, these substances cannot maintain a high degree of slipperiness for the required duration of time, due to the fact that they leach or disperse into the surrounding body fluids. The aim of this book is to describe the principle of lubrication, to outline a variety of methods for attaining a lubricous surface, and to describe the characteristics and properties of such lubricous surfaces. The technology for surface modification of polymers by grafting will find other applications than for lubrication, such as for improvement of the interfacial adhesion in polymer composites.