Hydrogen bonds inter-segmental

Polymer Adsorption. The driving force for adsorption typically is the en-thalpic interaction between the interface and the polymer segments. Exceptions include aqueous solutions near hydrophobic substrates. In that case, the driving force may include the hydrophobic interaction between water and the surface. The enthalpic interactions may be of various forms such as hydrogen bonding, inter-facial tension, van der Waals attraction, polar interactions, and electrostatic attractions. This enthalpic interaction is offset by the loss in conformational entropy... 

RNA is found in a repertoire of intra- and inter-molecular hydrogen bonding interactions. One famiUar structural element in an RNA molecule is the stem-loop, in which a noncomplementary segment separates two complementary stretches of nucleotides. 

Chart 3, Diagrammatic illustrations of (A and B) single- and double-stranded helical chains of leucine-containing polyphenylacetylene le stabilized by intra-and inter-chain hydrogen bonds and (C) theoretically possible conformations of chain segments of a substituted poly(phenylacetylene). 

FIGURE 19.9 X-ray crystal structure of citrate synthase. Part (a) is a spacefilling model and part (b) is a ribbon model, which emphasizes the a-helical segments of the protein chain and indicates that the enzyme is dimeric that is, it consists of two identical chains held together by hydrogen bonds and other inter-molecular attractions. 

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