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.

Dissipation of Pyrene‐Based Phenylboronic Acid‐Anchored Vesicular Self‐Assemblies: A Motif for Neurotransmitter Recognition

“…The magnified aromatic region 1 H‐NMR spectra was given in Figure S8 that showed suppressed NMR‐signals of 2 in self‐assembled state compared to its non‐self‐assembled state. From the above data it can be assumed that a variety of intermolecular non‐covalent interactions (that were likely to be hydrogen bonding, hydrophobic interactions and others) between the amphiphiles are responsible during the self‐aggregation process . We further studied the molecular aggregation pattern within the vesicular morphologies.…”

“…To have a detailed insight into the various intermolecular non‐covalent interactions i. e. the driving forces acting within the self‐assemblies, we conducted FTIR, 1 H‐NMR, UV‐vis and fluorescence spectroscopy of 2 in self‐assembled and non‐self‐assembled condition both. FTIR spectra of 2 in non‐self‐assembled state (in DMSO‐D 6 ) showed sharp transmittance band at 1543, 1659 and ∼3373‐3413 cm −1 owing to amide δ N‐H (amide II, bending), ν C=O (amide I, stretching) and co‐existence of ν N‐H (amide A) with ν O‐H peaks, respectively (Figure a) . When 2 was taken in DMSO‐D 6 ‐D 2 O(1:400 v/v, in self‐assembled state), the transmittance signals were shifted to 1547, 1635 and ∼3360‐3452 cm −1 (broad band), respectively (Figure a).…”

“…When 2 was taken in DMSO‐D 6 ‐D 2 O(1:400 v/v, in self‐assembled state), the transmittance signals were shifted to 1547, 1635 and ∼3360‐3452 cm −1 (broad band), respectively (Figure a). These shifts in stretching and bending frequencies clearly point out the involvement of intermolecular hydrogen bonding between carbonyl (C=O) and amide N−H moieties during self‐organisation process . Solvent dependent 1 H‐NMR was conducted with 2 in both non‐self‐assembled (in DMSO‐D 6 ) and self‐assembled condition (in DMSO‐D 6 ‐D 2 O (1:400 v/v)).…”

[2 + 2] Photocycloaddition Reaction Regulated the Stability and Morphology of Hydrogels

“…In the FTIR spectra shown in Fig. 4, the main absorption bands were observed at υ = 3445/3288, 1650/1622, and 1544 cm −1 , which originated from υ N-H (amide A), amide υ C=O (amide I), and υ N-H (amide II) vibrations, respectively [25,26]. The band regions indicated that an H-bond was formed between the amide groups.…”

Multifunctional, biocompatible and pH-responsive carbon nanotube- and graphene oxide/tectomer hybrid composites and coatings

“…Such dispersing approaches facilitate the bottom-up formation of highly ordered structures resulting in fascinating synergies, affording additional functions useful for a large number of applications ranging from sensing, catalysis, drug delivery and to tissue engineering. [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] In this regard, the use of de novo peptides, whose sequence, length, structure and assembly can be conveniently tailored, is an efficient and elegant route for the preparation of stable CNT dispersions, [31][32][33][34][35][36] as well as for the directed incorporation of CNT building blocks into hierarchical structures 31,[37][38][39][40] and functional devices. [41][42][43] In particular, peptide-functionalized nanomaterials are increasingly playing an important role in tissue and biomedical engineering for the development of novel synthetic scaffolds for cell culture in vitro that closely resemble in vivo conditions and show improved biomimetic properties.…”