Polymer Brushes by the “Grafting to” Method

This paper focuses on the attachment of densely grafted polymer layers (polymer brushes) to various inorganic and polymeric substrates by the “grafting to” method. A brief overview of synthesis of polymer brushes by the method is first provided, with emphasis on chemical approaches to polymer attachment. The second part of the paper covers the synthesis of polymer layers via a recently developed macromolecular anchoring layer approach. Several examples of application of the grafting technique are presented for generation of hydrophobic, hydrophilic, gradient, and switchable surfaces.

     

On the applicability of the “abt” concept

Kaiser's “abt” concept rests on the experimental establishment of a linear relation between band width at half height, b_0.5, and capacity ratio, k, according to His column specification quantity, h_real, is dependent on the square of the slope a, obtained from a linear regression analysis based on this relation. It is shown in the present paper that an improvement of the experimental conditions leading to a lower extra-column contribution to band broadening, b, introduces a tendency towards a negative curvature in the plot at low k values. The mean slope increases, and an uncritical linear regression would yield an h_real-value which is higher than before and which would be in the opposite direction to the requirements of a reliable column specification. Generally the linear regression analysis has to be moved to higher k regions in cases of curvature, especially as it is also shown that h_real is an estimation of the traditional HETP value, H∞, that would be obtained when k approaches infinity. This theoretically expected relation is a strong motivation for the use of h_real as a column specification, since the b_0.5-value associated with H∞ is expected to be practically independent of b.     

Comment on “The electrochemical Peltier heat of the standard hydrogen electrode reaction” by Zheng Fang et al.

Fang et al. recently performed electrochemical Peltier measurements, proposed an absolute entropy scale for the standard hydrogen electrode, and gave a value for the partial molar entropy of hydrogen ions in solution. That paper contains several ambiguities and omissions that should be resolved in order to make the information in the paper more useful. The thermodynamic state of the electron in their treatment is not fully specified, and the method used to calculate the partial molar entropy of solution phase hydrogen ions is not given. Furthermore, the calculation of partial molar entropy of solution phase hydrogen ions apparently omits the partial molar entropy of metal-phase electrons, a term that is necessary for such determinations if the starting point is electrochemical Peltier heat measurements. As a smaller matter, the paper overlooks specifying the units used for fugacity. The paper also overlooks previous work on absolute half-cell entropy.     

Influence of media polarity on the rate of activation of “dormant” chains in nitroxide‐mediated radical polymerization

Rate constants of decomposition of “living” polymeric adducts polystyrene (PS)‐TEMPO, poly‐4‐vinylpyridine‐TEMPO, PS‐SG1, and polyacrylic acid‐SG1 in different solvents were determined by the method of a competitive inhibition by means of electron spin resonance. It was found that with the increase in polarity of solvent, the values of constants become higher for all systems studied. This effect opens a new way of activating chains in nitroxide‐mediated radical polymerization. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Comment on “The effect of confinement on the electronic energy and polarizability of a hydrogen molecular ion” by Josimar Fernando da Silva,Fabricio Ramos Silva and Elso Drigo Filho,Int. J. Quantum Chem. 2016, 116, 497–503

Various conceptual and numerical errors reported in the paper cited in the title of this contribution are pointed out and clarified. Our main concern is the evident violation of the variational principle, which is used in that paper for the study of the confined hydrogen molecular ion to obtain both energies and properties.