ABSTRACT
I. INTRODUCTION Recently, many efforts have been dedicated to the study of macromolecules carrying ionized or ionizable groups. These synthetic poly electrolytes are important in industrial applications and also as simplified models of natural polyelectrolytes. Bipolymers such as proteins and nucleic acids are typical natural polyelectrolytes, and their functions in vivo stem basically from their higher ordered structures resulting from specific interactions among char acteristic structural elements (e.g., α-helices, /3-sheets). It should be of sig nificance to model such structural features of proteins and to define the interaction mechanism among the component chains for developing molecularly controlled polymeric materials that mimic biofunctions such as en zymatic catalysis and molecular recognition. One attractive approach is the recent work on template assembled synthetic proteins [1]. A template mol ecule directs the component chains into a proteinlike packing arrangement, e.g., a bundle of a-helices [2]. The amphiphilic property of the peptide blocks seems to be essential to stabilize such a bundle structure. A macro dipole moment of the α-helical rod would play a key role in assembling the structural elements [3,4]. Another approach is to use a Langmuir monolayer or a self-assembled monolayer, which is a useful tool for assembling mol ecules two-dimensionally [5]. We have devised a strategy in which purely synthetic poly electrolytes are aligned at the air-water interface or at the solid substrate. Poly(L-glutamic acid) (PLGA) has been chosen as a model element of a protein because of its ease of preparation and well-defined conformational characteristics in water.
