We synthesized three low-molecular-weight poly(glutamate)s poly(gamma-methyl L-glutamate) (PMLG), poly(gamma-ethyl L-glutamate) (PELG), and poly(gamma-benzyl L-glutamate) (PBLG) through living ring-opening polymerization of their alpha-amino acid-N-carboxyanhydride derivatives and then blended them with phenolic resin to control the secondary structures of these polypeptides. Each of the three binary blends exhibited a single glass transition temperature (differential scanning calorimetry) and a single-exponential decay of proton spin lattice relaxation times in the rotating frame [T(1 rho)(H); solid state nuclear magnetic resonance (NMR) spectroscopy], characteristic of a miscible system. The strength of the interassociative interactions depended on the nature of the hydrogen bond acceptor groups, increasing in the order phenolic/PELG > phenolic/PMLG > phenolic/PBLG, as evidenced through analyses using Fourier transform infrared (FTIR) spectroscopy and the Painter-Coleman association model. The fractions of alpha-helical conformations (measured using FTIR and solid-state NMR spectroscopy) of PMLG and PELG decreased initially upon increasing the phenolic content but increased thereafter; in contrast, the fraction of a-helical conformations of PBLG increased continuously upon increasing the phenolic contents. Using variable-temperature infrared spectroscopy to investigate the changes in the conformations of the secondary structures of the peptide segments in these three binary blends, we found that the a-helical conformation in these three blend systems correlated strongly with the rigidity of side-chain groups, the strength of the intermolecular hydrogen bonding with the phenolic resin, the compositions of phenolic resin, and the temperature. More interestingly, the content of a-helical conformations of the polypeptides in these phenolic/PBLG blends increased upon increasing the temperature.