A gelator (G2) synthesized from 1

2

4

5-benzene tetracarboxylic acid and 4-hydroxy pyridine at molar ratio of 1:4 was characterized by 1H-NMR and FT-IR.Supramolecular hydrogels were formed via cooling the aqueous solutions of G2 under ambient condition.The influence of cooling speed on the structure of the assembling fibers and the macroscopic properties of the gels was investigated via multiple techniques

including scanning electron microscopy (SEM)

differential scanning calorimetry (DSC) and rheology measurements.As decreasing the cooling speed

the fiber size becomes larger

and the gel stability becomes lower.Therefore it is possible to control the gel performances via the environmental stimulation.The gel possesses high mechanical properties as indicated by the rheology measurements.The DSC measurement reveals that the freezing water content for the gels becomes lower as increasing the gelator concentration.Compared with G1 synthesized from 1

2

4

5-benzene tetracarboxylic acid and 4hydroxy pyridine at molar ratio of 1:2

G2 gelled water at higher minimum gelator concentration (MGC) and gave the gel with lower gel-to-sol dissociation temperature (Tgel) at the same concentration.Environmental scanning electron microscopy (ESEM) was applied to study the naturally hydrated state of gels directly

it was also noticed that the fibrous networks observed by conventional SEM are similar to those obtained by ESEM

which means that the morphology does not change significantly under drying.The relationship between the assembled structure and properties is helpful for understanding the gel formation mechanism and makes the gels suitable for different applications.