The invention discloses materials that adsorb readily to the surfaces of body tissues in situ and provide a steric barrier between such tissues, so that tissue adhesions, which typically form following surgical procedures, are minimized. These materials contain a polymer of hydrophilic molecules such as polyethylene glycol (PEG) bound to a polymer that spontaneously adsorbs to biological tissue such as phenylboronic acid (PBA). The PEG-PBA co-polymer can be formed in a variety of geometries. The materials can also be used to coat prosthetics and other implants.