supriya maity - Academia.edu (original) (raw)

Papers by supriya maity

Research paper thumbnail of A Highly Stretchable, Tough, Self‐Healing, and Thermoprocessable Polyacrylamide–Chitosan Supramolecular Hydrogel

Macromolecular Materials and Engineering, 2018

chemically cross-linked, the resultant DN hydrogels sustain permanent damage after the first load... more chemically cross-linked, the resultant DN hydrogels sustain permanent damage after the first loading-unloading cycle, making them susceptible to fatigue. [6] However, DN hydrogels with hybrid chemical and physically cross-linked networks show impressive self-recovery and anti-fatigue properties owing to the restoration of the reversible physical cross-links on removal of load. [7-10] Other than DN hydrogel strategy, different approaches have been reported in the literature to synthesize hydrogels with enhanced mechanical properties. Examples include organic polymer networks cross-linked by inorganic clay, [11] slide-ring hydrogels in which α-cyclodextrin rings contained in PEG strings were cross-linked between different strings, [12] and non-swellable hydrogels prepared by cross-linking of tetra-arm hydrophilic and tetra-arm thermoresponsive polymer units, among others. [13] Although many of these hydrogels demonstrate excellent mechanical behavior, some of them require considerable synthetic efforts and almost all of them contain chemically cross-linked networks. The shape of these gels, once formed, is difficult to remold. These gels, owing to their already fixed network, are difficult candidates as injectable materials, potentially limiting their biomedical applications. Supramolecular hydrogels are an important class of hydrogels that are formed through only physical/non-covalent cross-linking interactions (hydrogen bonding, ionic interactions, metal-ligand interactions, host-guest interactions, etc.). Since non-covalent bonds can be reversibly formed and broken in response to an external stimulus (e.g., hydrogen bonds can be broken by heating the gel and reformed by cooling the resultant hot solution), these gels have emerged as potential candidates for application as functional materials in general, [14] and in tissue engineering applications in particular. [15] The main drawback of such hydrogels is that due to the relatively low strength of the non-covalent interactions responsible for their formation, these gels tend to be mechanically weak. [16] Consequently, the property of reversibility, although favorable for their applications as injectable biomaterials, becomes a deficiency when it comes to mimicking the load-bearing tissues, which requires robust mechanical performance. However, if these individually weak physical interactions can be harnessed such that they cooperatively provide effective energy dissipation mechanism, the resultant hydrogels could show vastly enhanced mechanical behavior and at Stretchable Hydrogels Polymerization of acrylamide in concentrated aqueous solution in the presence of chitosan and in the absence of covalent cross-linker leads to the formation of stiff and tough supramolecular polymer hydrogels that are self-healing, can be stretched up to ≈30 times their original length, and demonstrate rapid self-recovery, due to the inter-chain hydrogen bonds between polyacrylamide and chitosan acting as sacrificial bonds to dissipate energy. These gels show thermoplastic behavior and can be molded into different shapes after a heating-cooling cycle, maintaining reasonable mechanical strength. The gels can withstand repeated compressive loading-unloading cycles, exhibiting reliable load-bearing capacity.

Research paper thumbnail of A Highly Stretchable, Tough, Self‐Healing, and Thermoprocessable Polyacrylamide–Chitosan Supramolecular Hydrogel

Macromolecular Materials and Engineering, 2018

chemically cross-linked, the resultant DN hydrogels sustain permanent damage after the first load... more chemically cross-linked, the resultant DN hydrogels sustain permanent damage after the first loading-unloading cycle, making them susceptible to fatigue. [6] However, DN hydrogels with hybrid chemical and physically cross-linked networks show impressive self-recovery and anti-fatigue properties owing to the restoration of the reversible physical cross-links on removal of load. [7-10] Other than DN hydrogel strategy, different approaches have been reported in the literature to synthesize hydrogels with enhanced mechanical properties. Examples include organic polymer networks cross-linked by inorganic clay, [11] slide-ring hydrogels in which α-cyclodextrin rings contained in PEG strings were cross-linked between different strings, [12] and non-swellable hydrogels prepared by cross-linking of tetra-arm hydrophilic and tetra-arm thermoresponsive polymer units, among others. [13] Although many of these hydrogels demonstrate excellent mechanical behavior, some of them require considerable synthetic efforts and almost all of them contain chemically cross-linked networks. The shape of these gels, once formed, is difficult to remold. These gels, owing to their already fixed network, are difficult candidates as injectable materials, potentially limiting their biomedical applications. Supramolecular hydrogels are an important class of hydrogels that are formed through only physical/non-covalent cross-linking interactions (hydrogen bonding, ionic interactions, metal-ligand interactions, host-guest interactions, etc.). Since non-covalent bonds can be reversibly formed and broken in response to an external stimulus (e.g., hydrogen bonds can be broken by heating the gel and reformed by cooling the resultant hot solution), these gels have emerged as potential candidates for application as functional materials in general, [14] and in tissue engineering applications in particular. [15] The main drawback of such hydrogels is that due to the relatively low strength of the non-covalent interactions responsible for their formation, these gels tend to be mechanically weak. [16] Consequently, the property of reversibility, although favorable for their applications as injectable biomaterials, becomes a deficiency when it comes to mimicking the load-bearing tissues, which requires robust mechanical performance. However, if these individually weak physical interactions can be harnessed such that they cooperatively provide effective energy dissipation mechanism, the resultant hydrogels could show vastly enhanced mechanical behavior and at Stretchable Hydrogels Polymerization of acrylamide in concentrated aqueous solution in the presence of chitosan and in the absence of covalent cross-linker leads to the formation of stiff and tough supramolecular polymer hydrogels that are self-healing, can be stretched up to ≈30 times their original length, and demonstrate rapid self-recovery, due to the inter-chain hydrogen bonds between polyacrylamide and chitosan acting as sacrificial bonds to dissipate energy. These gels show thermoplastic behavior and can be molded into different shapes after a heating-cooling cycle, maintaining reasonable mechanical strength. The gels can withstand repeated compressive loading-unloading cycles, exhibiting reliable load-bearing capacity.