End-group location

Figure 11.11 Cartoon of possible end group locations, a) whole dendrimer end groups outside, b) whole dendrimer end groups backfolded, a) matched dendrimer end groups backfolded, a) matched dendrimer end groups backfolded. Outside end groups have a larger Rg...

Neutralizing these polyesters with different hydroxyamines made it possible to obtain stable micellar systems. The size of these micelles was shown to essentially be a function of the structure and the polyester molecular weight. The smallest micelles are obtained with diacid polyester of lower molecular weight. A model for the chain conformation of polyester in a micelle was proposed, taking into account the area occupied by one end group located at the micelle surface. Furthermore, such micelles were demonstrated to be able to solubilize non-neutralized polyester chains, as well as monomers like styrene or butylmethacrylate (BMA). 

II) Condensations of end groups located on the surface of crystallites with end groups of mobile chains in the amorphous phase. 

Ketoses are characterized by the ending ulose m their name Most nat urally occurring ketoses have their carbonyl group located at C 2 Like aldoses ketoses cyclize to hemiacetals and exist as furanose or pyranose forms... 

Detailed studies about metal deposition from the gas phase onto SAMs have been published [108-110], The central question for the system substrate/SAM/deposit there (as well as in electrochemistry) is the exact location of the deposited metal On top of the SAM or underneath Three clearly different situations are easily foreseen (Fig. 31). (1) Metal on top of the SAM. Depending on a strong or weak chemical interaction between metal and SAM (e.g., functional end group of the SAM), the deposit will spread out on top of the SAM or it will cluster on the SAM. (2) Metal penetrating the SAM (e.g., at defects in the SAM) and connecting to the metal substrate underneath the SAM. This configuration is often pictured as a mushroom, with a thin connective neck and a large, bulky head. (3) Deposited metal is inserted be-... 

Violene is constructed by a conjugated chain with two redox active chromophores. It is classified as two types (see Figure 2). As noted from the position of the end groups, one type is separated by an aromatic core and the other is located inside a cyclic 7c-system. In both cases, the colored species in this system are the radical ionic states. Thus, in general, the violene system does not show high redox stability (2). 

If a uniform distribution of end groups were present throughout the dendrimer, we would see the same Rg for both the labeled and the whole dendrimer. This is demonstrated by the illustration in Figure 11.11, where the end groups have different locations. Instead, we see a clear difference between the Rg values for the labeled units and the unlabeled dendrimers. The distribution of den-... 

All dendrimers consist of inner tertiary amines, located at the branching points of the various dendritic shells (layers). The amine-terminated dendrimers, furthermore, have basic primary amine end-groups. Basicity is therefore one of the most dramatic properties of the polypropylene imine) dendrimers, and has been studied via titration experiments and calculations. Titration experiments of the dendrimers have been performed in water using 1 M hydrochloric acid. Only two equivalence points are observed for DAB-J nJr-(NH2)4 in a ratio of 2 1. From these titrations, pKa values of 10.0 (primary amine groups) and 6.7 (tertiary... 

According to the principles of polycondensation, all of the above reactions will also take place during SSP. The conditions for the latter, however, are different as this process is carried out at lower temperatures in a non-homogeneous environment. In order to examine the kinetics of SSP, some assumptions have to be made to simplify the analysis. These are based on the idea that the reactive end groups and the catalyst are located in the amorphous regions. Polycondensations in the solid state are equilibrium reactions but are complicated by the two-phase character of the semicrystalline polymer. 

Cohen-Atiya and Mandler have also found that the extent of discharging process is significantly decreased in aprotic solutions and in the absence of oxygen. However, the influence of additional functional groups located at the other end of thiol molecules on the discharging process is still not fully understood. Possibly, such groups (e.g. carboxylic) affect accessibility of water to the electrode surface. 

Figure 9.1. Schematic representation of multimonomer pol5nnerization, where X- end group in the template R- end group of initiator pa - a probabihty that the radical wiU be reacting along the template pb - a probability that the radical wiU be reacting with a group located on the neighbor template.

BAs are a group of acids with a steroidal ring structure and a terminal carboxylic group located in the side chain (Fig. 5.4.1), and represent the major end products of cholesterol catabolism [2]. 

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