Monodisperse derivatives of poly(gamma -4-(hexadecyloxy)benzyl alpha ,L-glutamate) (PHBG-X, X = 3 or 4) with backbone sequence GluAsp(Glu(17)Asp)(x)GluGlu were prepared by reaction of 4-(hexadecyloxy)phenyldiazo-methane with the corresponding monodisperse poly(cr,L-glutamate) (PLGA) derivatives (PLGA-X, X = 3 or 4). PHBG-3 and -4 exhibited strong endotherms near 45 degreesC and weak endotherms near 86 degreesC when analyzed by differential scanning calorimetry. X-ray diffraction suggested that these polymers aggregate to form layerlike solid structures at room temperature, with extended alkyl side chains forming paraffinlike crystallites. Most of the side chain order disappears at the first melting transition; however, the layerlike structure remains. Both polymers are isotropic above the second melting transition; no ordered melts were observed at higher temperatures, possibly due to the small aspect ratios of PHBG-3 and -4. In contrast, polydisperse poly(gamma -4-(hexadecyloxy)benzyl alpha ,L-glutamate) (PDI = 1.2, DP = 98) (PHBG-P1), prepared from commercial PLGA, formed liquid crystalline (LC) phases between 97 and 105 degreesC.