title: Hydrophobic End-Modulated Amino-Acid-Based Neutral Hydrogelators: Structure-Specific Inclusion of Carbon Nanomaterials.
abstract: Hydrophobic end-modulated l-phenylalanine-containing triethylene glycol monomethyl ether tagged neutral hydrogelators (1-4) are developed. Investigations determine the gelators' structure-dependent inclusion of carbon nanomaterials (CNMs) in the self-assembled fibrillar network (SAFIN). The gelators (1, 3, and 4) can immobilize water and aqueous buffer (pH 3-7) with a minimum gelator concentration of 10-15 mg mL(-1). The hydrophobic parts of the gelators are varied from a long chain (C-16) to an extended aromatic pyrenyl moiety, and their abilities to integrate 1 D and 2 D allotropes of carbon (i.e., single-walled carbon nanotubes (SWNTs) and graphene oxide (GO), respectively) within the gel are investigated. Gelator 1, containing a long alkyl chain (C-16), can include SWNTs, whereas the pyrene-containing 4 can include both SWNTs and GO. Gelator 3 fails to incorporate SWNTs or GO owing to its slow rate of gelation and possibly a mismatch between the aggregated structure and CNMs. The involvement of various forces in self-aggregated gelation and physicochemical changes occurring through CNM inclusion are examined by spectroscopic and microscopic techniques. The distinctive pattern of self-assembly of gelators 1 and 4 through J- and H-type aggregation might facilitate the structure-specific CNM inclusion. Inclusion of SWNTs/GO within the hydrogel matrix results in a reinforcement in mechanical stiffness of the composites compared with that of the native hydrogels.
authors.affiliation: Department of Biological Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700032, India.
authors.forename: Pritam
authors.initials: P
authors.lastname: Choudhury
authors.affiliation: Department of Biological Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700032, India.
authors.forename: Deep
authors.initials: D
authors.lastname: Mandal
authors.affiliation: Department of Biological Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700032, India.
authors.forename: Sayanti
authors.initials: S
authors.lastname: Brahmachari
authors.affiliation: Department of Biological Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700032, India. bcpkd@iacs.res.in.
authors.forename: Prasanta Kumar
authors.initials: PK
authors.lastname: Das
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D020100:Hydrogels / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D049329:Nanostructures / Q000737:chemistry*; D037742:Nanotubes, Carbon / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D014867:Water
chemical_list: D000596:Amino Acids; D020100:Hydrogels; D037742:Nanotubes, Carbon; D010087:Oxides; D014867:Water; D002244:Carbon; D006108:Graphite
keywords: amphiphiles; carbon nanomaterials; hydrogels; neutral gelators; self-assembly; soft nanocomposites