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  • Nano Express
  • Open Access

Hofmeister Anion-Induced Tunable Rheology of Self-Healing Supramolecular Hydrogels

Nanoscale Research Letters201914:5

  • Received: 8 October 2018
  • Accepted: 29 November 2018
  • Published:


Physical gelation behaviors of a series of d-gluconic acetal-based derivatives bearing fatty alkyl amine moieties have been investigated. One of these molecules exhibits excellent gelation behaviors in water, and the resultant hydrogels are found to display self-healing properties. Interestingly, the elasticity and strength of the resulting gel can be tuned by the addition of different kinds of Hofmeister salts. The gel formation mechanism was proposed based on the analysis of FT-IR,1HNMR, and XRD, indicating that the main driving force for the self-assembly was the π-π stacking of the benzene rings in the aqueous solution system. Overall, our research provides an efficient approach for facilely tuning the properties of the d-gluconic acetal-based hydrogel.

Graphical Abstract image


  • Gelator
  • Rheology
  • Self-assembly
  • Self-healing
  • Thixotropy


Gels composed of low molecular mass gelators (LMMGs) can be obtained from the self-assembly of LMMGs via supramolecular interactions such as hydrogen bonding, van der Waals interactions, π-π stacking, and so on [113]. Over the last few decades, there has been rapid progress in the synthesis of LMMGs and supramolecular gels derived from LMMGs owing to the dynamic interaction of the gelators. They have attracted much attention not only as alternative materials for polymer gels but also as new types of soft materials capable of responding to multiple external stimuli. Furthermore, self-healing, an ability of systems to spontaneously repair their damage and improve the life-time of materials [1424], is one of the most fascinating properties of materials. They have found potential applications in the fields such as biological tissue [25], shape memory [24], and sensors [1424] as advanced materials. The development of self-healable supramolecular gels is one of the emerging fields in materials research. However, the reported self-healing gels are mainly polymeric gels [2531]. Even though they have enhanced mechanical properties, these synthetic polymer-based hydrogels do not have cell compatibility or degradability, which are critical for emerging biomedical applications [3234]. Low molecular weight gelators (LMWGs)-based self-healing organogels [3539] and hydrogels have been recently reported. To enhance the application of the resulting gels, efforts to develop molecular gels with tunable rheological properties are of pivotal importance, which will also provide new insights into the relationship between the molecular structure of gelators and gelation ability. In general, rheological behaviors of molecular gels can be modulated by introducing a new component into the original gel systems, such as metal complexes, neutral molecules, and inorganic salts [4045].

Although Hofmeister described the “specific ion” effect on protein folding and aggregation in 1888, the understanding of this effect still remains controversial [46, 47]. Hofmeister classified the ions according to their relative ability of stabilizing protein in aqueous solutions, resulting in the sequence shown in Fig. 1a. The ions on the left side of the series are kosmotropes (well-hydrated ions), and those on the right side are chaotropes (poorly hydrated ions). The former decreases and the latter increases protein solubility. The molecular basis of such phenomena has long been attributed to changes of structures in the water induced by salts [48]. However, recent evidence has suggested that the direct interactions between the ions and the macromolecules and their hydration shells result in the removal of the hydratation water molecules of the proteins, leading to their folding and precipitation, which could be the reason for the Hofmeister effect [4952]. These specific ion effects have later been observed in other areas, including colloid and surface chemistry, and macromolecular systems, such as proteins and polymers, etc. [5360]. Due to the strong effect on macromolecules dissolved in water, salts have also been used to monitor the properties of hydrogels [6168]. Rowan et al. [53] reported that they used the Hofmeister effect to controllably manipulate the mechanical properties of ethylene glycol-functionalized polyisocyanides-based polymer hydrogels. Wang et al. [6971] demonstrated that they produced hydrogels with high ductility, strength, recoverability, and fatigue resistance without modifying the gelatin chains or adding chemical crosslinks or fillers by soaking gelatin hydrogels in (NH4)2SO4 solutions at appropriate concentrations. However, it has only recently been appreciated in supramolecular chemistry and, more specifically, LWMGs-based hydrogels. For example, Mocerino et al. [6168] produced a macrocyclic low molecular weight hydrogelator, proline-functionalized calix [2531] arene, which showed ion-specific sol–gel transition, but the effect of the salts on the molecular organization of the hydrogel was not studied. Roy et al. [61] demonstrated that salts have the ability to regulate the morphology, material stiffness, and chirality properties of supramolecular hydrogels using hydrophobic peptide-based hydrogelators. Then, Roy et al. [66] reported that salts have a dramatic effect on the molecular self-assembly of the aromatic dipeptide amphiphiles in aqueous media. Salts affect the structure of the enzyme network, which, in turn, influence the enzyme kinetics and the corresponding nucleation and growth of the nanostructures. Escuder et al. [6168] prepared smart supramolecular hydrogels from a bolaamphiphilic l-valine derivative in aqueous solutions of different salts. The hydrogels selectively responded to different ions and strengths of them were either reinforced or weakened. Recently, our group reported a multifunctional d-gluconic acetal-based gelator with a long alkyl chain which could form gels with outstanding self-healing ability [72, 73]. We also reported the multifunctional gel systems based on the amine-acid two-component systems which showed high-efficiency self-healing, room-temperature phase selective gelation, and dye removal capabilities [74]. Based on these works, here we designed a series of organic compounds (Gn, n = 1–4, Fig. 1b) derived from d-gluconical bearing alkyl amine moieties. These compounds were highly efficient LMWGs based on hydrogen-bonding interaction and π-π stacking force. Hydrogen bonding was one of the main self-assembly driving forces of supramolecular gels. By introducing an amino or hydroxyl in alkyl chain, or substituting the active hydrogen of hydroxy by methyl iodide, hydrogen bonding sites were added or adjusted. The compounds were serving as novel and highly efficient LMWGs (cf. Fig. 1b).
Fig. 1
Fig. 1

a Hofmeister anions. b Chemical structures of gelator Gn (n = 1–4) examined

Initially, the gelation abilities of Gn in various solvents were summarized in Additional file 1: Table S1. It was found that Gn were potent gelators in certain organic solvents. Except for G3 and G4, the others have the abilities to gelatinize water. In particular, G1-gel was found to have self-healing properties during the test. The G1 gel can undergo an instant self-healing process upon mechanical damage. Furthermore, we explored the effect of salts on the properties of the gels, especially the recovery properties.

To the best of our knowledge, few reports have been disclosed with tunable rheology of supramolecular gels by addition of a slight amount of Hofmeister salts.



d-Gluconic acid, 3, 4-dichlorobenzaldehyde, β-hydroxyethylenediamine, 2, 2-iminodi (ethylamine),1-aminohexane, and N-propyl-propane-1,3-diamine were purchased from Shanghai Jingchen Scientifical Co., Ltd. The chemical reagents were commercially available and directly utilized without further purification. 2,4-(3, 4-Dichloro) benzylidene methy-d-gluconate was synthesized by the methods reported previously [75]. Characterizations of a new compound Gn are provided in Additional file 1. Synthetic routes of Gn are shown in Additional file 1: Scheme S1. The detailed synthetic procedures and characterization data of Gn are given in Additional file 1.

Gel Preparation

Gelation tests for Gn in organic solvents were investigated by a typical tube inversion method. Gn were mixed in an organic solvent (1 mL) in a sealed test tube, which was heated until the solid was completely dissolved and then cooled to room temperature. Finally, the test tube was inversed to observe whether the solution inside could still flow [6971]. Gelation was considered to have occurred when a homogeneous substance was obtained which exhibited no gravitational flow, and it was denoted by “G.” Solution and solid-like gel may coexist within a system as “partial gels (PG)”. Systems, in which only solution was obtained, were referred to as solution (S). If clear solutions were obtained when they are hot, but precipitation occurs when they are cooled down to room temperature, these systems are denoted by “precipitation (P).” In an insoluble system (I), gelator could not be dissolved even at the boiling point of the solvent. The critical gelation concentrations (CGCs) means the minimum amount of gelator required to immobilize 1 mL of solvent.


1H NMR spectroscopic measurements were carried out on Bruker DPX 400 MHz spectrometer. In the temperature experiments, 10 mg of gelators was dissolved in 0.5 mL of D2O-d6. The temperature was 25 °C.

Preparation of “Co-Gels” for Salt-Effects on Gel Rheology

A total of 20 mg gelator was added into 1.0 mL water. The resulting mixture was heated until it formed a clear solution and allowed to cool down to ambient temperature to form gels. For comparison, a reference gel was prepared only by introducing 20 mg gelator into 1.0 mL 0.5 M salt solution.

Field Emission Scanning Electron Microscope

The morphologies of the xerogels were obtained by a Hitachi S-4800 SEM instrument operating at 3–5 kV. Samples were prepared by dropping the diluted solution of gels on the thin aluminum sheets and then dried under vacuum for 24 h. The samples were coated with a thin layer of Au before the experiment.

FT-IR Spectroscopy

IR spectra were collected by a FTS3000 spectrometer with KBr pellets. The xerogels were prepared by drying hydrogels on glass slides under vacuum for 24 h.

Powder X-Ray Diffraction

Powder X-ray diffraction (PXRD) diagrams of xerogels which were prepared from hydrogels were obtained by using a Bruker D8-S4 (CuKα radiation, λ = 1.546 Å). The d spacing values were calculated by Bragg’s law (nλ = 2d sinθ).

Rheology Measurements

Rheology experiments were carried out with a strain-controlled rheometer (Anton Paar Physica MCR 301) equipped with steel-coated parallel-plate geometry (15 mm diameter). The gap distance was fixed at 0.5 mm. A solvent trapping device was placed above the plate and measurement was set at 20 °C in order to avoid solvent evaporation. The frequency sweep at a constant strain of 0.1% was obtained from 0.1 to 100 rad s−1. Strain sweep was performed in the 0.01–1000% range at a constant frequency (1 Hz). The time sweep was conducted to observe the recovery property of the gel. First, a constant strain of 0.1% was applied on the sample. Then a constant strain of 100% was applied to destroy the sample. And then a constant strain (0.1%) was applied again. The storage modulus G′ and the loss modulus G′′ of the sample were monitored as functions of time in this experiment.

Results and Discussion

Specific Ion Effects on the Solution-to-Gel Equilibrium

The gelation abilities of Gn are summarized in Additional file 1: Table S1. Fifteen different solvents were employed to evaluate their gelation behaviors. Compounds G3 and G4 could not gelatinize water. The hydrogel of G2 exhibits weakly.The CGCs (a minimum gel concentration) of hydrogel based on G1 is 25 mM. Here, compound G1 was chosen for the further study of the Hofmeister effect on the hydrogelation behavior.

The anions (as their sodium salts) employed in this study covered all of the relative positions in the Hofmeister series: kosmotropes (SO42−, S2SO32−, HPO42−, F), borderline (Br, Cl, NO3), and chaotropes (I, ClO4,SCN).

CGC measurements (“Gel Preparation” section) were carried out in order to investigate the effect of a series of salts on the gelator’s gelation ability. As shown in Additional file 1: Table S2, the CGCs of G1 in water increased gradually, by adding salt ions (0.5 M), from the kosmotropes ions (salt-out ions, e.g., SO42−) to the chaotropes ions (salt-in ions, such as the SCN).

Because the higher the viscosity B coefficient of an anion is, the stronger it makes hydrogen bonds with water, by studying the correlation between the viscosity B coefficient of different anions and CGCs, the influence of different anions on the viscosity B coefficient of aqueous solution can be characterized [75] The fitting result was 0.543 (In Fig. 2a). When removed the certain points (ClO4, F, S2O32−), the result was fitting as high as 0.932 (In Fig. 2b). The viscosity B coefficients are increasing from chaotropes ions to kosmotropes ions. The kosmotropes ions (such as SO42−) can improve the hydrogen bonding between water molecules and decrease the number of free water, resulting in the decline of the interaction between the gelator and water,which promoted precipitation and self-assembly of gelators. Therefore, the CGCs decreased. The effect of chaotropes ions (such as SCN) is opposite. The existence of irregular ions (ClO4, F, S2O32−) indicated that the effect of salt ions on the properties of hydrogels could not be fitted by a single parameter (the viscosity B coefficients).
Fig. 2
Fig. 2

a CGCs (0.5 M salts) with the viscosity B coefficients. b CGCs (0.5 M salts) except the special points with the viscosity B coefficients. c Plot of the effect of anions (the salt concentration from 0 to 5 M) and Tgel of G1 hydrogel as a function of salt concentration. d Plot of the effect of anions (the salt concentration from 0 to 0.7 M) and Tgel of G1 hydrogel as a function of salt concentration

Tgel is another important parameter to evaluate the gelation abilities of gelator in various solvents. The higher Tgel means the better thermal stability performance. Figure 2c, d reveals that the types and concentration of anions have strong influence on Tgel of G1 hydrogels (see the detailed data in the Additional file 1: Table S3). Except for Iand ClO4, the Tgel of G1 hydrogel at certain salt concentration (for example salt concentration is 0.5 M) decreased gradually from kosmotropes ions to chaotropes ions. It is well known that Kosmotropes anions cancause the “salting-out” effect in proteins and reduce the solubility of the gelators resulting in the formation of the solid-like fibrillar network. Accordingly, “salting-in” or chaotropic anions produced a solubilization effect on the gelator network. In other words, kosmotropic anions strengthen the fibrillar network, whereas chaotropic anions produce a weakening effect on the hydrogel. Naturally, Tgel shows the decreasing trend from kosmotropes ions to chaotropes ions. As shown in Fig. 2d when increasing the concentration of all anions from 0 to 1 M, the Tgel of G1 hydrogel gradually increased. It may be that upon addition of salt ions, the 3D network structure of G1 hydrogel becomes dense, which raises Tgel of G1 hydrogel.

Salt-Induced Tunable Rheology of Self-Healing Supramolecular Hydrogels

As shown in Fig. 3a, upon shaking, liquid appeared leading to the sol-gel mixture. After resting for less than 10 min, the gel recovered. The self-healing properties of G1 gels were further demonstrated by cutting the gels into two pieces and then putting these pieces together. It was shown that the pieces joined together and merged into a continuous gel block (Fig. 3a). Next, we then explored the effect of salts on the the recovery properties of the gels.
Fig. 3
Fig. 3

a Illustration of self-healing properties of the G1 gels (2.0% w/v) obtained from undoped gel and blue dye-doped gel. b Time scan tests under alternating strain of 0.1% and 100% of G1 (2.5% w/v) with Hofmeister salts (concentration is 0.5 M) with a fixed frequency at 1 Hz at 25 °C

The rheological behaviors of the supramolecular gels are important for their real-life applications, in particular, thixotropy and self-healing. In this section, to explore the effect of the Hofmeister salts on the mechanical and thixotropic behaviors of G1 hydrogels, the rheological properties of the G1 hydrogels(2.5% w/v) containing the a series of Hofmeister salts (salt concentration is 0.5 M) were examined.

When the frequency varied,the Additional file 1: Figure S2a revealed that Hofmeister anions can regulate the G′ value from 110,000 to 350,000 Pa and the range of the G′ value was 68.57%. Except for certain anions (Fand ClO4), the G′ value decreased gradually from kosmotropes to chaotropes. Similarly, the Hofmeister anions can turn the G′′ value from 11,100 to 65,100 Pa and the range was 82.95%. The loss modulus(the G′ value) is a parameter reflecting the viscosity of the materials. The relationship between the loss modulus and Hofmeister salts was consistent with that between the viscosity B coefficients and Hofmeister salts. Figure 3b revealed that Hofmeister anions could regulate the recovered G′ value from 95,600 to 340,000 Pa. The range of the G′ value was 71.88%. Except for the specific anions (F), the G′ value decreased gradually from kosmotropes to chaotropes. Besides, the step-strain measurement showed the recovery ratios of G′ after the first cycle (90.74%, 85.93%, 82.08%, 100%, 90.77%, 100%, 95.56%, 96.48%, 95.97%, 88.12%, 93.89% respectively), and these results illustrated that G1 hydrogel was of excellent thixotropic and self-healing properties.

To my best knowledge, this is the first time to regulate the thixotropy of hydrogels by using the Hofmeister anions. It also provides a simple and feasible method to regulate thixotropy.

FT-IR Spectroscopy

FT-IR was one of the effective methods to study the driving force of gels. FT-IR of G1 hydrogel (2.5% w/v) adding different salt solutions (0.5 M)were carried out and the results were shown in the Fig. 4a. The Fig. 4a of G1 xerogel revealed that about 2937 and 2844 cm−1 respectively, were characteristic for asymmetric stretching vibration (vas) and symmetric stretching vibration (vs) of methylene. With the addition of SO42−, the corresponding bands were observed at 2946 and 2844 cm−1. This observation supported the weaker Van der Waals (VDW) interactions between the alkyl chains in the presence of the anions. In addition, the stretching band of O–H overlapped with that of N–H and appeard at 3369 cm−1. The stretching band of C=O was observed at 1640 cm−1. For the G1-SO42− and G1-S2O32− xerogel, the corresponding bands were observed at 3421, 1644 cm−1 and 3383, 1642 cm−1 respectively which were blue-shifted in contrasted with the G1 hydrogel. The xerogel of other anions showed similar trend. These results indicated that O–H, N–H, and C=O were involved in hydrogen bonding and the hydrogen bonding of hydrogel weakened because of the addition of kosmotropes anions of Hofmeister series. However, the thermodynamic stability reflected from Tgel and gelation capacity reflected from CGC were gradually getting better with the addition of kosmotropes anions. It was suggesting that in the self-assembly process, the hydrogen bonding was less than other forces and it was not the main driving force of self-assembly.
Fig. 4
Fig. 4

a FT-IR spectra of G1 xerogel (2.5% w/v) in the presence of some kosmotropes ions (concentration is 0.5 M). b 1H NMR spectra of G1 (2.5% w/v) in D2O addition of Hofmeister salts (concentration is 0.5 M). c WXRD spectra of 2.5% G1 xerogel obtained from water in the presence of Hofmeister anions (concentration is 0.5 M). d Possible self-assembly mechanism of G1 hydrogel with a schematic representation of the postulated molecular packing model (a: energy-minimized structure of G1)



In fact, π-π interaction was recognized as one of the main driving force for the physical gelation of gelator G1 in the water as further evidenced by 1H NMR measurements (cf. Fig. 4b).

1H NMR spectra of the gelator G1 (2.5% w/v) with/without Hofmeister salts in D2O (salt concentration is 0.5 M) were compared, as shown in Fig. 4b. In Fig. 4b, one of the H-shifts on the benzene ring of G1 hydrogel appeared at 7.959 ppm in pure [d6]D2O. After the addition of SO42−, S2O32−, HPO42−, and F, the peaks of C–H protons shifted to 7.745, 7.846, 7.901, and 7.904 ppm, respectively. Compared with G1 in pure [d6]D2O, the signals of C–H protons on the benzene ring of the G1 mixed with kosmotropes anions (SO42−, S2O32−, HPO42−, and F) moved upfield, which indicated that the π-π stacking effects between benzene rings were enhanced. Correspondingly after the addition of I, ClO42−, and SCN, the peaks of C–H protons shifted to 7.993, 8.007, and 8.130 ppm, respectively. Compared with G1 in pure [d6]D2O, the signals of C–H protons on the benzene ring of the G1 mixed with chaotropes anions (I, ClO42−, and SCN) moved downfield, which suggested that the π-π stacking effects between benzene rings were weakened. In Fig. 4b with the addition of transition region anions (Cl, Br, and NO3), the signals of C–H protons on the benzene ring shifted slightly, indicating that the π-π stacking effects between benzene rings were not influenced obviously.

From kosmotropes to chaotropes, H-shift on the benzene ring gradually moved toward the low field and the π-π stacking effect between benzene rings was gradually weakened. The result was consistent with the macro performance of the gelators (the changing trends of CGC and Tgel). It also reveals that the main driving force for the self-assembly is the π-π stacking force of the benzene rings in the aqueous solution system.


The morphologies of some typical gels were examined by SEM. As shown in Additional file 1: Figure S3a, ropelike left-handed helical structures with a pitch of about 50 nm are observed for G1 hydrogels. Ropelike left-handed helical fibers with a 30 nm average diameter that formed a 3D network were observed in aqueous solution of SO42− (concentration is 0.5 M, Additional file 1: Figure S3b). In addition, G1 hydrogels are composed of complex and entangled three-dimensional networks, and the fiber bundles are thick and dense. However, it can be seen that due to the salt-out effect of SO42−, the gelator is precipitated out and wound into a more dense three-dimensional network structure. But due to the influence of Cl which belongs to the transition region of kosmotropes and chaotropes on the solubility, the gelators self-assemble into a mesh of fiber structure (Additional file 1: Figure S3c). In the image of hydrogels formed in the presence of the salt-in anion SCN, it is shown that the fibers were broken and folded loosely together without the formation of the three-dimensional structure, so that the ability to bind solvents is relatively weak (Additional file 1: Figure S3d). Obviously, the morphologies and thermodynamic stability of the gel showed the same trend. In other words, the aggregation of gelators decreases from kosmotropes and chaotropes.

Powder X-Ray Diffraction

To explore the possible packing modes of the gelator molecules in water with the addition of Hofmeister salts in particular, wide-angle XRD (WXRD) of the G1 xerogels were examined. As shown in Fig. 4c, XRD patterns of the G1 xerogel from water showed four main diffraction peaks centered at 2θ = 19.267 (d = 0.46030 nm), 2θ = 28.262 (d = 0.31551 nm), 2θ = 34.071 (d = 0.26292 nm), and 2θ = 38.843 (d = 0.23165), and the ratio of d-spacing values is about 1:1/√2:1:√3 indicating that the self-assembly of the G1 xerogel from water is composed of hexagonal closs packing possibly [76]. In addition, there was a main raction peak centered at 2θ = 23.389 (d = 0.38002 nm), and d = 0.38 nm is the characteristic of π-π stacking force of the benzene rings. It reveals that the main driving force for the self-assembly is the π-π stacking force of the benzene rings in the aqueous solution system [77, 78]. In Fig. 4c, patterns of the G1 xerogel from Na2SO4 aqueous solution (concentration is 0.5 M) exhibited four diffraction peaks centered at 2θ = 19.084 (d = 0.46468 nm), 2θ = 28.075 (d = 0.31757 nm), 2θ = 33.901 (d = 0.26421 nm), and 2θ = 38.683 (d = 0.23257 nm), and it proved that the addition of SO42− did not affect packing modes of the gelator molecules.While patterns of the G1 xerogel from NaSCN aqueous solution (concentration is 0.5 M) exhibited diffraction peaks centered at 2θ = 26.184 (d = 0.34006 nm), 2θ = 30.263 (d = 0.29508 nm), 2θ = 38.904 (d = 0.23130 nm), and 2θ = 38.683 (d = 0.23257 nm), and patterns of the G1 xerogel from aqueous solution (salt concentration is 0.5 M) exhibited four diffraction peaks centered 2θ = 23.076 (d = 0.38511 nm), 2θ = 29.563 (d = 0.30191 nm), 2θ = 32.101 (d = 0.27860 nm), and 2θ = 39.165 (d = 0.22982 nm). The ratio of d-spacing values were all 1:1/√2:1:√3 indicating that the self-assembly of the G1 xerogel from water is mainly composed of hexagonal closs packing [76]. At the same time, except the above-mentioned main peaks, other peaks also appear in the Fig. 4c, indicating that other packing modes may also exist in self-assembly process. The above results indicate that the addition of different anions had great influence on the properties of gels but it did not change the packing mode of the hydrogel self-assembly process.

The Gel Formation Mechanism

Furthermore, the energy-minimized structure of G1 (Additional file 1: Figure S4) suggests that the length of the molecule G1 is 1.46 nm. Consequently, a feasible self-assembly mode of G1 gelators in water is proposed (Fig. 4d). As shown in Fig. 4d, G1 molecules were not distributed in a simple plane, but stacked with each other at a certain angle by π-π stacking force of the benzene rings. Then the fine nanofibers were formed. The XRD analysis showed that fine nanofibers aggregated model were based on hexagonal close packing. Further self-association of the one-dimensional fibers leads to rope-like fiber bundles with different sizes via VDW forces provided by long carbon chains. Eventually, a 3D network formed through intertwining of fiber bundles with the water confined.


In conclusion, we have described a novel multi-functional gelator based on d-gluconic acetal-based derivatives, which exhibited highly efficient self-healing properties. We also provided a simple and effective method for regulation of thixotropy of LMWGs. Furthermore, the hydrogel formation mechanism was proposed based on the analysis of FT-IR, 1HNMR, and XRD. Further studies on the component structure–gel property relationship and exploring applications of these materials are still in progress.



H nuclear magnetic resonance


A minimum gel concentration


Combined gel


Field emission scanning electron microscope


Fourier transform infrared spectroscopy


Low molecular mass gelators


Powder X-ray diffraction


The temperature of phase transition



All authors gratefully acknowledge the financial support from the National Natural Science Foundation of China (grant nos. 21676185 and 21476164) in the design of the study, collection, and analysis. The Tianjin science and technology innovation platform program (no. 14TXGCCX00017) who participated in the interpretation of the data and in writing the manuscript also funded the study.


This research was supported financially by the National Natural Science Foundation of China (grant nos. 21676185 and 21476164), the Tianjin science and technology innovation platform program (no. 14TXGCCX00017).

Availability of Data and Materials

All data generated or analyzed during this study are included in this published article and in Additional file.

Authors’ Contributions

JZ conceived and carried out the experiments, analyzed the data, and wrote the manuscript. BZ and QC carried out the experiments and analyzed the data. BZ and JS designed the study, analyzed the data, and wrote the manuscript. All authors read and approved the final manuscript.

Competing Interests

The authors declare that they have no competing interests.

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Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Authors’ Affiliations

School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, China
The Co-Innovation Center of Chemistry and Chemical Engineering of Tianjin, Tianjin, 300072, China
Renai College of Tianjin University, Tianjin, 301636, China


  1. Terech P, Weiss RG (1997) Low Molecular Mass Gelators of Organic Liquids and the Properties of Their. Gels Chem Rev 97:3133–3160View ArticleGoogle Scholar
  2. Estroff LA, Hamilton AD (2004) Water gelation by small organic molecules. Chem Rev 104:1201–1218View ArticleGoogle Scholar
  3. Sangeetha NM, Maitra U (2005) Supramolecular gels: functions and uses. Chem Soc Rev 34:821–836View ArticleGoogle Scholar
  4. Liu KQ, He PL, Fang Y (2011) Progress in the studies of low-molecular mass gelators with unusual properties. Sci China Chem 54:575–586View ArticleGoogle Scholar
  5. Ishi-I T, Shinkai S (2005) Supramolecular Dye Chemistry. Top Curr Chem 258:119–160View ArticleGoogle Scholar
  6. Yan N, Xu ZY, Diehn KK, Raghavan SR, Fang Y, Weiss RG (2013) How do liquid mixtures solubilize insoluble gelators? self-assembly properties of pyrenyl-linker-glucono gelators in tetrahydrofuran-water mixtures. J Am Chem Soc 135:8989–8999View ArticleGoogle Scholar
  7. Liu J, He PL, Yan JL, Fang XH, Peng JX, Liu KQ, Fang Y (2008) An organometallic super gelator with multiple stimulus responsive properties. Adv Mater 20:2508–2511View ArticleGoogle Scholar
  8. Li YG, Liu KQ, Liu J, Peng JX, Feng XL, Fang Y (2006) Amino acid derivatives of cholesterol as “latent” organogelators with hydrogen chloride as a protonation reagent. Langmuir 22:7016–7020View ArticleGoogle Scholar
  9. Liu QT, Wang YL, Li W, Wu LX (2007) Structural characterization and chemical response of a agcoordinated supramolecular gel. Langmuir 23:8217–8223View ArticleGoogle Scholar
  10. Wang YL, Li W, Wu LX (2009) Organic-inorganic hybrid supramolecular gels of surfactant-encapsulated polyoxometalates. Langmuir 25:13194–13200View ArticleGoogle Scholar
  11. Wang XF, Duan PF, Liu MH (2012) Universal chiral twist via metal ion induction in the organogel of terephthalic acid substituted amphiphilic l-glutamide. Chem Commun 48:7501–7503View ArticleGoogle Scholar
  12. Miao WG, Yang D, Liu MH (2015) Multiple-stimulus-responsive supramolecular gels and regulation of chiral twists: the effect of spacer length. Chem Eur J 21:7562–7570View ArticleGoogle Scholar
  13. Boothroyd S, Miller AF, Saiani A (2013) From fibres to networks using self-assembling peptides. Faraday Discuss 166:195–207View ArticleGoogle Scholar
  14. Shirakawa M, Fujita N, Shinkai S (2005) A stable single piece of unimolecularly pi-stacked porphyrin aggregate in a thixotropic low molecular weight gel: a one-dimensional molecular template for polydiacetylene wiring up to several tens of micrometers in length. J Am Chem Soc 127:4164–4165View ArticleGoogle Scholar
  15. Weng W, Jamieson AM, Rowan SJ (2007) Structural origin of the thixotropic behavior of a class of metallosupramolecular gels. Tetrahedron 63:7419–7431View ArticleGoogle Scholar
  16. Yu XD, Chen LM, Zhang MM, Yi T (2014) Low-molecular-mass gels responding to ultrasound and mechanical stress: towards self-healing materials. Chem Soc Rev 43:5346–5371View ArticleGoogle Scholar
  17. Xu ZY, Peng JX, Yan N, Yu H, Zhang SF, Liu KQ, Fang Y (2013) Simple design but marvelous performances: molecular gels of superior strength and self-healing properties. Soft Matter 9:1091–1099View ArticleGoogle Scholar
  18. Dawn A, Shiraki T, Ichikawa H, Takada A, Takahashi Y, Tsuchiya Y, Lien LTN, Shinkai S (2012) Stereochemistry-dependent, mechanoresponsive supramolecular host assemblies for fullerenes: a guestinduced enhancement of thixotropy. J Am Chem Soc 134:2161–2171View ArticleGoogle Scholar
  19. Mukhopadhyay P, Fujita N, Takada A, Kishida T, Shirakawa M, Shinkai S (2010) Regulation of a realtime self-healing process in organogel tissues by molecular adhesives. Angew Chem Int Ed Eng 49:6338–6342View ArticleGoogle Scholar
  20. Lescanne M, Grondin P, D’Aléo A, Fages F, Pozzo J-L, Monval OM, Reinheimer P, Colin A (2004) Thixotropic organogels based on a simple n-hydroxyalkyl amide: rheological and aging properties. Langmuir 20:3032–3041View ArticleGoogle Scholar
  21. Brinksma J, Feringa BL, Kellogg RM, Vreeker R, van Esch J (2000) Rheology and thermotropic properties of bis-urea-based organogels in various primary alcohols. Langmuir 16:9249–9255View ArticleGoogle Scholar
  22. Miyamae K, Nakahata M, Takashima Y, Harada A (2015) Self‐healing, expansion–contraction, and shape‐memory properties of a preorganized supramolecular hydrogel through host–guest interactions. Angew Chem Int Ed 54:8984–8987View ArticleGoogle Scholar
  23. Huynh T-P, Haick H (2016) Self-healing, fully functional, and multiparametric flexible sensing platform. Adv Mater 28:138–143View ArticleGoogle Scholar
  24. Jin H, Huynh T-P, Haick H (2016) Self-healable sensors based nanoparticles for detecting physiological markers via skin and breath: toward disease prevention via wearable devices. Nano Lett 16:4194–4202View ArticleGoogle Scholar
  25. Feng Q, Wei K, Lin S, Xu Z, Sun Y, Shi P, Li G, Bian L (2016) Mechanically resilient, injectable, and bioadhesive supramolecular gelatin hydrogels crosslinked by weak host-guest interactions assist cell infiltration and in situ tissue regeneration. Biomaterials 101:217–228View ArticleGoogle Scholar
  26. Zhang M, Xu D, Yan X, Chen J, Dong S, Zheng B, Huang F (2012) Self-healing supramolecular gels formed by crown ether based host-guest interactions. Angew Chem Int Ed 51:7011–7015View ArticleGoogle Scholar
  27. Burnworth M, Tang L, Kumpfer JR, Duncan AJ, Beyer FL, Fiore GL, Rowan SJ, Weder C (2011) Optically healable supramolecular polymers. Nature 472:334–337View ArticleGoogle Scholar
  28. Appel EA, Biedermann F, Rauwald U, Jones ST, Zayed JM, Scherman OA (2010) Supramolecular crosslinked networks via host−guest complexation with cucurbit[8]uril. J Am Chem Soc 132:14251–14260View ArticleGoogle Scholar
  29. Nakahata M, Takashima Y, Yamaguchi H, Harada A (2011) Redox-responsive self-healing materials formed from host–guest polymers. Nat Commun 2:511View ArticleGoogle Scholar
  30. He L, Fullenkamp DE, Rivera JG, Messersmith PB (2011) Ph responsive self-healing hydrogels formed by boronate-catechol complexation. Chem Commun 47:7497–7499View ArticleGoogle Scholar
  31. Wang Q, Mynar JL, Yoshida M, Lee E, Lee M, Okuro K, Kinbara K, Aida T (2010) High-water-content mouldable hydrogels by mixing clay and a dendritic molecular binder. Nature 463:339–343View ArticleGoogle Scholar
  32. Yu X, Cao X, Chen L, Lan H, Liu B, Yi T (2012) Thixotropic and self-healing triggered reversible rheology switching in a peptide-based organogel with a cross-linked nano-ring pattern. Soft Matter 8:3329–3334View ArticleGoogle Scholar
  33. Sahoo P, Sankolli R, Lee H-Y, Raghavan SR, Dastidar P (2012) Gel sculpture: moldable, load-bearing and self-healing non-polymeric supramolecular gel derived from a simple organic salt. Chem Eur J 18:8057–8063View ArticleGoogle Scholar
  34. Vidyasagar A, Handore K, Sureshan KM (2011) Soft Optical Devices from Self-Healing Gels Formed by Oil and Sugar-Based Organogelators. Angew Chem Int Ed 50:8021–8024View ArticleGoogle Scholar
  35. Silva D, Natalello A, Sanii B, Vasita R, Saracino G, Zuckermann RN, Doglia SM, Gelain F (2013) Synthesis and characterization of designed bmhp1-derived self-assembling peptides for tissue engineering applications. Nanoscale 5:704–718View ArticleGoogle Scholar
  36. Roy S, Baral A, Banerjee A (2013) An amino-acid-based self-healing hydrogel: modulation of the selfhealing properties by incorporating carbon-based nanomaterials. Chem Eur J 19:14950–14957View ArticleGoogle Scholar
  37. Roy B, Bairi P, Chakraborty P, Nandi AK (2013) Synthesis and Characterization of New Metal-free and Metallophthalocyanines Substituted with Tetrathiadiazamacrobicyclic Moieties. Supramol Chem 25:335–343View ArticleGoogle Scholar
  38. Nanda J, Biswas A, Banerjee A (2013) Single amino acid based thixotropic hydrogel formation and phdependent morphological change of gel nanofibers. Soft Matter 9:4198–4208View ArticleGoogle Scholar
  39. Ceylan H, Urel M, Erkal TS, Tekinay AB, Dana A, Guler MO (2013) Supramolecular polymers: mussel inspired dynamic cross‐linking of self‐healing peptide nanofiber network. Adv Funct Mater 23:2081–2090View ArticleGoogle Scholar
  40. Gao S, Wang S, Ma J, Wu Y, Xuwei F, Marella RK, Liu K, Fang Y (2016) Salt tunable rheology of thixotropic supramolecular organogels and their applications for crystallization of organic semiconductors. Langmuir 32:12805–12813View ArticleGoogle Scholar
  41. Poolman JM, Boekhoven J, Besselink A, Olive AG, van Esch JH, Eelkema R (2014) Variable gelation time and stiffness of low-molecular-weight hydrogels through catalytic control over self-assembly. Nat Protoc 9:977–988View ArticleGoogle Scholar
  42. Chen L, Raeburn J, Sutton S, Spiller DG, Williams J, Sharp JS, Griffiths PC, Heenan RK, King SM, Paul A, Furzeland S, Atkins D, Adams DJ (2011) Tuneable mechanical properties in low molecular weight gels. Soft Matter 7:9721–9727View ArticleGoogle Scholar
  43. Kleinsmann AJ, Weckenmann NM, Nachtsheim BJ (2014) Phosphate-triggered self-assembly of N-[(uracil-5-yl) methyl] urea: A minimalistic urea-derived hydrogelator. Chem Eur J 20:9753–9761View ArticleGoogle Scholar
  44. Zhang Y, Yang ZM, Yuan F, Gu HW, Gao P, Xu B (2004) Molecular recognition remolds the selfassembly of hydrogelators and increases the elasticity of the hydrogel by 106-fold. J Am Chem Soc 126:15028–15029View ArticleGoogle Scholar
  45. Bhattacharya S, Srivastava A, Pal A (2006) Modulation of viscoelastic properties of physical gels by nanoparticle doping: Influence of the nanoparticle capping agent. Angew Chem 118:3000–3003View ArticleGoogle Scholar
  46. Hofmeister F (1888) Zur lehre der wirkung der salze. Zweite mittheilung. Arch Exp Pathol Pharmakol 24:247–260View ArticleGoogle Scholar
  47. Kunz W, Henle J, Ninham BW (2004) zur lehre von der wirkung der salze’ (about the science of the effect of salts): franz hofmeister's historical papers. Curr Opin Colloid Interface Sci 9:19–37View ArticleGoogle Scholar
  48. Collins KD, Washabaugh MW (1985) The hofmeister effect and the behaviour of water at interfaces. Q Rev Biophys 18:323–422View ArticleGoogle Scholar
  49. Chen X, Flores SC, Lim SM, Zhang Y, Yang T, Kherb J, Cremer PS (2010) Specific anion effects on water structure adjacent to protein monolayers. Langmuir 26:16447–16454View ArticleGoogle Scholar
  50. Pegram LM, Record MT Jr (2008) Thermodynamic origin of hofmeister ion effects. J Phys Chem B 112:9428–9436View ArticleGoogle Scholar
  51. Chen X, Yang T, Sho Kataoka A, Cremer PS (2007) Specific ion effects on interfacial water structure near macromolecules. J Am Chem Soc 129:12272–12279View ArticleGoogle Scholar
  52. Collins KD (2004) Ions from the hofmeister series and osmolytes: effects on proteins in solution and in the crystallization process. Methods 34:300–311View ArticleGoogle Scholar
  53. Jaspers M, Rowan AE, Paul H, Kouwer J (2015) Tuning hydrogel mechanics using the hofmeister effect. Adv Funct Mater 25:6503–6510View ArticleGoogle Scholar
  54. Hyde AM, Zultanski SL, Waldman JH, Zhong YL, Shevlin PF (2017) General Principles and Strategies for Salting-Out Informed by the Hofmeister Series. Org Process Res Dev 21:1355–1370View ArticleGoogle Scholar
  55. Zhang YJ, Cremer PS (2006) Interactions between macromolecules and ions: the hofmeister series. Curr Opin Chem Biol 10:658–663View ArticleGoogle Scholar
  56. Zhang YJ, Cremer PS (2010) Chemistry of hofmeister anions and osmolytes. Rev Phys Chem 61:63–83View ArticleGoogle Scholar
  57. Lo Nostro P, Ninham BW (2012) Hofmeister phenomena: an update on ion specificity in biology. Chem Rev 112:2286–2322View ArticleGoogle Scholar
  58. Jungwirth P, Cremer PS (2014) Beyond hofmeister. Nat Chem 6:261–263View ArticleGoogle Scholar
  59. Kima MH, Parka H, Nama HC, Parkb SR, Jungb J-Y, Parka WH (2018) Injectable methylcellulose hydrogel containing silver oxide nanoparticles for burn wound healing. Carbohydr Polym 181:579–586View ArticleGoogle Scholar
  60. Park H, Kim MH, Yoon YI, Park WH (2017) One-pot synthesis of injectable methylcellulose hydrogel containing calcium phosphate nanoparticles. Carbohydr Polym 157:775–783View ArticleGoogle Scholar
  61. Roy S, Javid N, Frederix PWJM, Lamprou DA, Urquhart AJ, Hunt NT, Halling PJ, Ulijn RV (2012) Dramatic specific-ion effect in supramolecular hydrogels. Chem Eur J 18:11723–11731View ArticleGoogle Scholar
  62. Chen L, Pont G, Morris K, Lotze G, Squires A, Serpell LC, Adams DJ (2011) Salt-induced hydrogelation of functionalised-dipeptides at high pH. Chem Commun 47:12071–12073View ArticleGoogle Scholar
  63. Becker T, Goh CY, Jones F, McIldowie MJ, Mocerino M, Ogden MI (2008) Proline-functionalised calix[4]arene: an anion-triggered hydrogelator. Chem Commun 33:3900–3902View ArticleGoogle Scholar
  64. Joshua M, Swann G, Bras W, Topham PD, Howse JR, Ryan AJ (2010) Effect of the hofmeister anions upon the swelling of a self-assembled ph-responsive hydrogel. Langmuir 26(12):10191–10197View ArticleGoogle Scholar
  65. Longyu L, Ja-Hyoung R, Thayumanavan S (2013) Effect of hofmeister ions on the size and encapsulation stability of polymer nanogels. Langmuir 29:50–55View ArticleGoogle Scholar
  66. Roy S, Javid N, Sefcik J, Halling PJ, Ulijn RV (2012) Salt-induced control of supramolecular order in biocatalytic hydrogelation. Langmuir 28:16664–16679View ArticleGoogle Scholar
  67. He Q, Huang Y, Wang S (2017) Hofmeister Effect‐Assisted One Step Fabrication of Ductile and Strong Gelatin Hydrogels. Adv Funct Mater 18:1705069Google Scholar
  68. Nebot VJ, Ojeda-Flores JJ, Smets J, Fernndez-Prieto S, Escuder B, Miravet JF (2014) Rational design of heat-set and specific-ion-responsive supramolecular hydrogels based on the hofmeister effect. Chem Eur J 20:14465–14472View ArticleGoogle Scholar
  69. Wang H, Wang FF, Tang HT, Zhang JY, Yang YJ (2007) Self-assembly and Gelation of Benzylidene Sorbitol Derivatives in Organic Solvents. Acta Chim Sin 65:1057–1063Google Scholar
  70. Randall M, Failey CF (1927) The activity coefficient of gases in aqueous salt solutions. Chem Rev 4:271–284View ArticleGoogle Scholar
  71. Gurau MC, Lim S-M, Castellana ET, Albertorio F, Kataoka S, Cremer PS (2004) On the mechanism of the Hofmeister effect. J Am Chem Soc 126:10522–10523View ArticleGoogle Scholar
  72. Guan X, Fan K, Gao T, Ma A, Zhang B, Song J (2016) A novel multi-stimuli responsive gelator based on d-gluconic acetal and its potential applications. Chem Commun 52:962–965View ArticleGoogle Scholar
  73. Chen S, Zhang B, Zhang N, Ge F, Bao Z, Wang X, Song J (2018) Development of self-healing d‑gluconic acetal-based supramolecular ionogels for potential use as smart quasisolid electrochemical materials. ACS Appl. Mater. Interfaces 10:5871–5879Google Scholar
  74. Liu J, Li J, Lin P, Zhang N, Han X, Zhang B, Song J (2016) Flexible and highly transparent twocomponent organogels with enhanced viscoelasticity for self-healing materials and room-temperature phase-selective gelation. Chem Commun 52(97):13975–13978View ArticleGoogle Scholar
  75. Molinier V, Kouwer PJ, Bouchu A, Mackenzie G, Queneau Y, Goodby JW (2006) Self-organizing properties of monosubstituted sucrose fatty acid esters: the effects of chain length and unsaturation. Chem Eur J 12:3547–3557View ArticleGoogle Scholar
  76. Banerjee A, Palui G (2008) Pentapeptide based organogels: the role of adjacently located phenylalanine residues in gel formation. Soft Matter 4(7):1430–1437View ArticleGoogle Scholar
  77. Rajamalli P, Prasad E (2011) Low molecular weight fluorescent organogel for fluoride ion detection. Org Lett 13:3714–371778View ArticleGoogle Scholar
  78. Liu JW, Yang Y, Chen C-F, Ma J-T (2010) Novel anion-tuning supramolecular gels with dual-channel response: reversible sol−gel transition and color changes. Langmuir 26:9040–9044View ArticleGoogle Scholar


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