Preparation of supramolecular network materials by means of amylose helical assemblies

• Published in: Polymer (Guilford) Vol. 140; pp. 73 - 79
• Main Authors: Kadokawa, Jun-ichi, Shoji, Takuya, Yamamoto, Kazuya
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 28.03.2018; Elsevier BV
• Subjects: Amylose; Amylose helix; Assemblies; Carbohydrates; Catalysis; Chemical synthesis; Conformation; Crosslinking; Enzymes; Glutamic acid; Handedness; Hydrogels; Inclusion complex; Inclusion complexes; Molecular chains; Molecules; Network material; Phosphorylase; Polymerization; Polymers; Polysaccharides; Saccharides; Amylose helix; Network material; Inclusion complex
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2018.02.023

Amylose, a natural polysaccharides, is a well-known functional material, because it forms double helix and inclusion complex assemblies depending on whether guest compounds are present or not, owing to its left-handed helical conformation. Amylose is precisely synthesized by phosphorylase-catalyzed enzymatic polymerization. In this study, we investigated the phosphorylase-catalyzed enzymatic polymerization initiated from maltoheptalose (primer for the polymerization)-grafted poly(γ-glutamic acid) in the presence of different feed ratios of a guest polymer, poly(ε-caprolactone) (PCL). In the absence of PCL or presence of less amount of PCL, the reaction mixtures totally turned into hydrogel form, predominantly composed of amylose double helixes. On the other hand, aggregates, which were largely composed of amylose inclusion complexes, were formed in the reaction mixtures in the presence of larger amount of PCL. The analytical results indicated that double helix cross-linking points participated into the formation of larger network structure, whereas smaller network structure was fabricated from inclusion complex cross-linking points. These structures on molecular level hierarchically constructed different macroscopic network sizes, leading to difference in the material forms. [Display omitted] •Material forms were changed by guest/primer feed ratios in enzymatic polymerization.•Depending on guest feed ratios, network sizes by amylose helixes were changed.•Predominant formation of amylose double helix gave rise to larger network.•Smaller network largely composed of the amylose inclusion complex was formed.