Collagen and other polyelectrolyte-based materials in an electrochemical environment are studied, modeled, and developed as the seat of an electrically controlled mechanical deformation:​ or electrical response to a mechanical deformation. Experimental results are presented concerning the electromechanical transduction properties of collagen fibers and membranes. Collagen is known to attain a positive charge at low pH, negative charge at high pH, and little or no charge in the region of neutral pH. Techniques are developed for delineating the electromechanical coupling with the electrical and mechanical variables under temporal and spatial control.

When a collagen fiber, constrained at both ends and immersed in an aqueous medium, is subjected to an electric field it deforms. This instance of electromechanical coupling is studied in the pH region 3-12 by application of a dc field ranging in strength up to 10 volts/cm. The observed response of the collagen fibers to the electric field under a variety of conditions, together with the results of a detailed study of the polyelectrolyte character of the fibers in the absence of a field, lead to the conclusion that the phenomenon is electro kinetic in origin. A theoretical model is developed characterizing electromechanical transduction properties of deformable charged polyelectrolyte membranes in an aqueous electrolyte environment. This model is motivated in part by the results of experiments performed with collagen fibers. In order to test the applicability of the model and the nature of the coupling coefficients, dynamic electromechanical experiments have been devised employing collagen membranes coupled hydrodynamically to an external mechanical system.Observation of the frequency response in a range of chemical environments suggests now transduction can lead to:​ (1) a mechanical excitation of the external system in response to an electrical stimulus applied to the membrane, and (2) a potential drop across the membrane in response to a mechanical stimulus applied to the external system. A dynamic approach was used to distinguish between rate processes associated with the electrolyte and electrodes from those of the membrane.

Relations expressing the proportionality of mass flux and current flow through the membrane to pressure and potential drops across it are derived. The treatment employs a cylindrical pore model as a means of self-consistently expressing the balance between internal electrical and viscous stresses, where equivalent pores represent interstices in the polyelectrolyte matrix. The electric force density is written in terms of the field due to membrane charge and electrolyte counter fons (accounting for ionic strength, pH, etc.), and the potential drop across the pore. The smoothing out of internal pore flows on both sides of the membrane over a distance on the order of the pore spacing is then accounted for by incorporating the effective ohmic and viscous resistances of these transition regions. Hence, electromechanical coupling is finally expressed in terms of measurable, macroscopic velocity, current, potential and pressure drops, and coupling coefficients Y₁₁, Y₁₂, Y₂₁, Y₂₂, which are functions of pore radius, pore spacing, membrane thickness, electrolyte viscosity and conductivity and internal polyelectrolyte electric field.

Membranes of rat tail tendon collagen used in experiments are produced in our laboratory by solubilizing the tendons, precipitating collagen fibrils from solution, and casting and crosslinking a membrane of these fibrils. Electrical conductance and hydrodynamic permeability are direct functions of the processing conditions, and are adjusted at will.