Fiber formation/architectures

J.-M. Lehn et al. designed helical architectures via the pre-programming of molecular self-assembly through specific non-bonding interactions [116, 117]. The formation of chiral fiber-like architectures had been also observed from non-chiral monomers such as in the gels of bis-urea building blocks [118]. 

Nucleosomes are connected to one another by linker DNA of variable length and the linker-binding histone HI protein (Fig. 1) (7). These long arrays of nucleosomes spontaneously condense to form helical arrays of nucleosomes, termed the 30-nm fiber after its apparent diameter (Fig. 1) (8). Additional condensation and compaction of chromatin occur through intemucleosomal interactions. One important internucleosomal interaction required for chromatin fiber formation is the interaction of a highly acidic patch of histone H2A with the histone H4 tail (8). Ultimately, these internucleosomal interactions form interphase chromatin with an unknown architecture (Fig. 1) (9). 

In addition to the process parameters, a number of system parameters play an important role in fiber formation and the obtained structure. System parameters include molecular weight, molecular weight distribution, polymer architecture, and solution properties. Solution properties play a particularly important role. In relation to their impact on the electrospinning process, these factors can be ranked as follows polymer concentration, solvent volatility, and solution conductivity. 

Bolaform amides (G4-G8) wherein both ends of the sufiiciently long hydrophobic alkyl chain were linked to hydrophilic moieties via amide linkage were reported to be excellent gelators of various solvents. Extended HBN via amide-amide hydrogen bonding leading to ID tape architecture was proposed to be responsible for fiber formation [52] (Fig. 4.3). 

Fig. 10 Micro/nanostructure engineering of functional materials, (a) Network architecture (route 2) with respect to normal fiber formation, (b) Modification of micro/nanostructure of 3D interconnecting fiber network...

In the following sections, self-assembled architectures based on the two main peptide secondary structures (a-helices and /S-sheets) are discussed. This is followed by some examples of fiber formation constituted by dipeptide... 

Patel, N. Lee, L.J. Effects of fiber mat architecture on void formation and removal in liquid composite molding. Polym. Compos. 1995, 16, 386 399. 

MIC of Materials. Many cases have been documented of the biodeterioration by bacteria and/or fungi of architectural building materials, stonework, fiber-reinforced composites, polymeric coatings, and concrete.66 Biodeterioration then proceeds by the processes of staining, patina formation, pitting, etching, disaggregation, and exfoliation. (Dexter)5... 

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