On the Nature of the Interaction between Starch and Iodine

Abstract

(1) It is postulated that the interaction between starch and iodine in the amylose-iodine complex is of dipolar nature. (2) A model for such dipolar interaction is proposed and the necessity for a cooperative effect is discussed. (3) The interaction energy is calculated as a function of a parameter x and it is shown that this parameter possesses a critical value at which a ``condensation'' of iodine into the complex occurs. (4) It is demonstrated that it is physically reasonable for this parameter to attain its critical value. (5) It is shown that additional stabilization may occur as a result of the formation of a resonating ``polyiodine'' chain at high dipolar interaction having a I–I distance and heat of formation which compares favorably with experiment. (6) Application of the theory is made in discussing the stability of the polyvinyl alcohol-iodine complex. (7) The color of these complexes is discussed in terms of the theory.

Relationship between enthalpy relaxation and water sorption of ball-milled potato starch

“…It is known that parts of the straight chains in the non-reducing termini of the amylopectin side chains form double helices (Kainuma and French, 1972). These helices are arranged in parallel composition with hydrogen bonding between adjoining glucose residues (Stein and Rundle, 1948). This is the basis of crystal formation in starch.…”

Sorption and permeation of iodine in water‐swollen poly(vinyl alcohol) membranes and iodine complex formation

“…These results show that the rate of the formation of the PVA-iodine complex was smaller than that of the iodine sorption. It is well known that Young's modulus of a polymer gel, E, is expressed as a function of the volume fraction of the polymer, V,, as follows19-22: log E = log A + B log V, (6) where A and B are constants. Young's moduli of water-swollen PVA membranes are plotted against the volume fraction of polymer, V, = 1 -H,, in Figure 4, to show that eq.…”

Iodine L-edge XAFS study of linear polyiodide chains in amylose and α-cyclodextrin

“…More recently, Teitelbaum et al concluded that the major component of iodine in the amylose helix is in the form of I 5 from resonance Raman and iodine Mössbauer spectroscopies (Teitelbaum et al, 1978, Teitelbaum et al, 1980. As for the interaction in the complex, it is not resolved whether main contribution comes from dispersion force, or it originates from induced dipole in iodine molecules (Stein & Rundle, 1948), or there are charge transfer from amylose oxygen to iodine chains (Murakami, 1954).…”