Mussel‐Inspired Adhesive Nano‐Filler for Strengthening Polyacrylamide Hydrogel

Abstract

Hydrogels are emerging as one of the most attractive water‐containing polymeric materials for many biomedical and industrial engineering applications. Cellulose nanocrystals (CNC) are often used as filler material to overcome the drawbacks of conventional hydrogels. However, weak frictional interaction of CNC with the polymeric backbone of hydrogels in the presence of water has limited its applications. Herein, we report a mussel‐inspired preparation of a new bio‐based nano‐filler by grafting dopamine (DOPA) over the carboxylated cellulose nanocrystal (CCN), which has been obtained by oxidizing CNC extracted from sawdust. The swelling of polyacrylamide (PAM) hydrogels has been significantly suppressed by the incorporation of the modified filler. In contrast, the mechanical properties like Young's modulus, tensile strength, and toughness of PAM hydrogels increased remarkably indicating a strong interaction of CNC‐DOPA with the PAM chains. For instance, the tensile strength increased from 19 kPa for the CNC‐PAM to 39 kPa for the CCN‐DOPA‐PAM. Interestingly, insertion of only 1 % (w/w) CCN‐DOPA has led to the enhancement of the mechanical strength of PAM even more than that caused by the insertion of 4 % pristine CNC. The spectroscopic data along with the morphological analysis of the composite hydrogels suggest strong hydrogen bonding of DOPA moiety and the PAM backbone is responsible for this incredible improvement of the mechanical strength.

Preparation of shape memory polyurethane/modified cellulose nanocrystals composites with balanced comprehensive performances

“…It could be found from FTIR spectra (Figure 2A) that all samples showed main characteristic peaks at approximately 2907 cm À1 (symmetric and asymmetric C H stretching vibrations), 1432 cm À1 (CH 2 bending vibration), 1032 and 1057 cm À1 (C O stretching vibration), indicating the preservation of the basic CNC structure. [33][34][35] After the modification of TDI, the TDI-CNC sample exhibited decreased area at 3385 cm À1 ( O H stretching vibration) than that of the pristine CNC, due to the partially consumption of hydroxyl groups on the CNC surface. Moreover, two new peaks appeared at 1718 cm À1…”

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“…13 Therefore, controlling the polymer chemistry and the synthesis conditions allows us to tailor the properties of crosslinked gels. Chemically crosslinked gels are relatively durable under large de-formation and their mechanical strength is correlated with the degree of swelling, which can be enhanced by incorporating filler materials 14 and other monomers that can form their own network interpenetrating with polymer gels. 15 The nature of the polymer and the desired properties of the resultant gels are decisive to choose the synthesis method of hydrogels and organogels.…”

Polyampholyte Hydrogels with pH-Dependent Swelling for Controlled Catch and Release of Model Dyes

“…[13] Therefore, controlling the polymer chemistry and the synthesis conditions allow us to tailor the properties of crosslinked gels. Chemically crosslinked gels are relatively durable under large deformation and their mechanical strength is correlated with the degree of swelling (DS) which can be enhanced by incorporating filler materials [14] and other monomers that can form their own network interpenetrating with polymer gels. [15] The nature of the polymer and the desired properties of the resultant gels are decisive to choose the synthesis method of hydrogels and organogels.…”