Mechanics of photosynthesis assisted polymer strengthening

Abstract

Abstract Plant cells utilize photosynthesis to produce glucose that is delivered to selected locations to form stiff polysaccharides (e.g., chitin, chitosan, and cellulose), which strengthen the plant structures. Such a photosynthesis-assisted strengthening behavior in plants has rarely been imitated in synthetic material systems. We here propose a synthetic polymer system embedded with extracted plant chloroplasts, which allow for the photosynthesis-assisted mechanical strengthening of the polymer matrix. The strengthening mechanism relies on an additional crosslinking reaction between the photosynthesis-produced glucose and side groups within the polymer matrix. We develop a theoretical framework to model the photosynthesis-assisted strengthening behaviors of polymers. The glucose production of the embedded chloroplasts will be first modeled with a general photosynthesis theory, and the exportation of glucose to the polymer matrix is modeled with an enzyme-assisted mass transport theory. Next, a polymer strengthening network model with glucose molecules as additional crosslinkers is presented. Effects of the illumination period, the concentration of embedded chloroplasts, and the light intensity on the stiffness strengthening are studied. The theoretical results consistently agree with the experimental results of the photosynthesis-assisted polymer strengthening.