accomplished by varying the ratio of amide to ester bonds in the final polymer.3 This can

be accomplished via co-polymerization of monomers containing both types of bonds, but

more frequently by the condensation of monomers with terminal amines and terminal

acids. The characteristic biological degradability of PEAs is of particular interest for this

research. The structure of the PEA polymer backbone, in particular, provides a

straightforward route to biodegradable materials because of the possibility of

incorporating biologically related molecules. Various biological molecules have been

incorporated into the polymer backbone, including amino acids, amino alcohols, amino

acid sequences and peptides.1'4-11 The resultant biologically based PEA polymer

molecules have been examined for biodegradability because of their unique biological

character.

 Acyclic diene metathesis (ADMET) chemistry is used to produce polymers of

unique and fixed architectures utilizing diene monomers.12'13 ADMET is a condensation

polymerization reaction that connects molecules through terminal alkenes and releases

the small molecule ethylene. The release of this gaseous small molecule is the driving

force for this reaction and allows high molecular weight to be reached with a variety of

monomers.12-17 The 2nd generation Grubbs' catalyst (Figure 1) has been shown to be very

tolerant of a variety of functional groups.14-17 The stability of the 2nd generation Grubbs'

catalyst and the versatility of ADMET led us to believe we could contribute some

important insights with regards to amino acid polymers. The possibility of making amino

acid polymers that are enzymatically degradable was particularly attractive.

 A second area of research focuses on the chirality of the side chain of the amino

acid residues. The naturally occurring amino acids are chiral molecules. It has been