@article {43895, title = {Solution processed cellulose/melanin films and fibres}, journal = {Green Materials }, volume = {5}, year = {2017}, month = {JUN}, type = {Article}, abstract = {Melanins constitute a class of biomacromolecules that are abundant in nature. Although they exhibit a unique range of physical and chemical properties, their intractable nature has precluded their dissolution in common solvents and facile processing into functional materials. The authors found that commercially available 40 wt\% tetrabutylammonium hydroxide (Tbah) solution could yield stable solutions of synthetic and natural melanins at ambient conditions and the dissolution rate could be accelerated by microwave radiation. Transmission electron microscopy images clearly show the disruption of the aggregated structure of melanins in Tbah. Scanning electron microscopy images of melanin/Tbah solutions precipitated in acetone revealed that melanins are dissolved and regenerated and not merely dispersed. To the best of the authors{\textquoteright} knowledge, this is the first report demonstrating a facile approach to solution processing melanins with other biopolymers, which allows leverage of many unique properties of melanins. As an illustrative example, the authors demonstrate here the successful fabrication of cellulose/melanin composite films and fibers and their significant dye absorption capacity (62\% reduction) with methylene blue.}, doi = {10.1680/jgrma.17.00003}, author = {Farsa, Ram and Pimpalkar, Nikhil and Shete, Abhijit P. and Shanmuganathan, Kadhiravan} } @article {46304, title = {Sustained release insect repellent microcapsules using modified cellulose nanofibers (mCNF) as pickering emulsifier}, journal = {Colloids and Surfaces A-Physicochemical and Engineering Aspects}, volume = {582}, year = {2019}, month = {DEC }, pages = {Article Number:123883}, type = {Article}, abstract = {

We report here an approach to encapsulate N, N-diethyl-3-methylbenzamide (DEET), an insect repellent, through interfacial polycondensation using modified cellulose nanofiber (CNF) as pickering emulsifier. We found that stearic acid functionalized CNF (mCNF) can be used to form stable pickering emulsions (oil-in-oil and water-in-oil), and further encapsulate DEET using interfacial polycondensation with very high encapsulation efficiency of about 98\%. Another major advantage of this approach is that mCNF can act both as pickering emulsifier and also strengthen the barrier properties of microcapsules resulting in significant reduction in release rate of DEET. Interpretation of the release profiles using standard mathematical models proposed by Ritger-Peppas show a factor of three reduction in release rate constant for the microcapsules reinforced with mCNF.

}, keywords = {Cellulose nanofiber, Controlled release, Microcapsules, Nanocomposite, nanoparticle, Pickering emulsion}, issn = {0927-7757}, doi = {10.1016/j.colsurfa.2019.123883}, author = {Kadam, Sandip L. and Yadav, Prashant and Bhutkar, Siddhant and Patil, Vishal D. and Shukla, Parshuram G. and Shanmuganathan, Kadhiravan} } @article {48453, title = {Synthesis of N-oxyethylene substituted imidazolium-based zwitterions as a recyclable solvent for cellulose dissolution}, journal = {Cellulose}, volume = {30}, year = {2023}, month = {JAN}, pages = {87-109}, type = {Article}, abstract = {

Cellulose is a readily available, renewable, and natural biomaterial that has the potential to replace synthetic fibres. However, their processing to shaped materials such as fibre or film is still complex and restricted due to its insolubility in most conventional solvents. Herein, we present the synthesis and cellulose dissolution characteristics of a new class of recyclable zwitterions composed of tethered N-oxyethylene substituted imidazolium cation and alkyl carboxylate anion. Investigations on cellulose dissolution showed that increasing the alkyl chain length of carboxylate anion and introduction of oxyethylene unit on imidazolium ring led to better cellulose dissolution ability, and up to 12\% (w/w) cellulose could be dissolved in aqueous zwitterions at 105 degrees C. The thermal behavior of zwitterions and their cellulose solutions was characterized by TGA and found to be more stable than the NMMO and Lyocell solutions. Rheological characterization of cellulose solutions revealed viscoelastic behavior and zero shear viscosity of 6-12\% (w/w) cellulose solution in hexanoate containing aqueous zwitterion was 555 to 5900 Pa.s at 120 degrees C. The characteristics of cellulose solution indicate its potential for processing to cellulose fibre by extrusion through a tiny spinneret. Physico-chemical analysis of regenerated cellulose indicates that zwitterions cause no adverse effect on cellulose structure and morphology during dissolution. The zwitterions are recovered after the cellulose regeneration process, and the recovery was found to be 99.6\% after purification using the ion-exchange method.

}, keywords = {Carboxylate anion, Cellulose dissolution, Oxyethylene unit, Regenerated cellulose, Rheology, zwitterions}, issn = {0969-0239}, doi = {10.1007/s10570-022-04883-1}, author = {Jadhav, Sachin and Ganvir, Vivek and Singh, Madan Kumar and Shanmuganathan, Kadhiravan} } @article {49385, title = {Structure and properties of the cellulose fibres spun from imidazolium-based carboxylate functionalized zwitterionic liquid}, journal = {CARBOHYDRATE POLYMERS}, volume = {348}, year = {2025}, month = {JAN }, keywords = {cellulose, Direct dissolution, Zwitterionic liquid}, issn = {0144-8617}, doi = {10.1016/j.carbpol.2024.122804}, author = {Jadhav, Sachin and Singh, Dhirendra and Gupta, Deepika and Ganvir, Vivek and Singh, Madan Kumar and Shanmuganathan, Kadhiravan} } @article {49809, title = {Sustained release polyurethane microcapsules by interfacial polycondensation using aromatic diols}, journal = {Reactive \& Functional Polymers}, volume = {216}, year = {2025}, month = {NOV}, pages = {106460}, type = {Article}, abstract = {

Polyurea-urethane (PUU) microcapsules prepared via interfacial polymerization have gained significant interest due to their tunable size and membrane thickness, high loading efficiency, and scalability. Although several aromatic and aliphatic diols and polyols have been used to produce PU foams and films, the use of aromatic diols to synthesize PUU MICs via interfacial polymerization is an unexplored domain due to the restricted solubility of aromatic diols in water. This report highlights the successful preparation of PUU microcapsules using an aromatic diol (benzene-1,4-dimethanol, BDM) to encapsulate dimethyl phthalate (DMP), a model insect repellent. The developed PUU microcapsules exhibited a high \% encapsulation efficiency of 92 \% and a size range of 1-20 mu m. Differential scanning calorimetry (DSC) thermograms revealed a significantly high glass transition temperature (Tg) of 143 degrees C as compared to 108 degrees C in the case of PUU MICs with aliphatic diols. Release studies confirm enhanced barrier properties for aromatic diol-based MICs as compared to aliphatic ethylene glycol-based PUU MICs, and interpretation of the release profile using the Weibull Model reveals that Fickian diffusion is the dominant mechanism in the release of DMP. These microcapsules can be used in high-performance applications such as composites, coatings, electronics, and construction.

}, keywords = {interfacial polymerization, Microencapsulation, polyurethane, sustained release}, issn = {1381-5148}, doi = {10.1016/j.reactfunctpolym.2025.106460}, author = {Yadav, Prashant and Ravikumar, Aniruddha and Ambade, V. Ashootosh and Shanmuganathan, Kadhiravan} } @article {50049, title = {Simple two-step gelation process to strengthen 3D printed carboxy methyl cellulose gels}, journal = {Cellulose}, volume = {33}, year = {2026}, month = {MAR}, pages = {2015-2030}, type = {Article}, abstract = {

Carboxymethyl cellulose (CMC) is a water-soluble cellulose ether that is widely utilized in hydrogel applications due to its exceptional water absorption and biocompatibility. This study reports a simple two step strategy to make mechanically robust CMC gels without any additional chemical crosslinkers and how it could be leveraged to strengthen 3D printed CMC gels. These hydrogels, prepared through acid-induced gelation followed by freeze-thawing, exhibited a compressive modulus of 12.4 +/- 0.92 kPa and a compressive strength of 491.0 +/- 18.1 kPa. They could be leveraged for strengthening 3D printing hydrogels of intricate shapes by direct ink writing. Small amplitude oscillatory shear (SAOS) tests indicated an order of magnitude higher storage modulus for freeze-thawed gels (FC) as compared to only acid-induced CMC gels (HCMC). Nonetheless, stress relaxation experiments revealed that FC, as well as HCMC gels, relax at similar time scales. FC gels exhibited clear birefringence under crossed polarizers, indicating molecular ordering that is consistent with the presence of ordered/crystalline domains. Such ordered domains likely contribute to the higher elastic modulus and compressive strength observed in FC gels as compared to HCMC gels.

}, keywords = {3D printing, Carboxymethyl cellulose, cellulose, Gels}, issn = {0969-0239}, doi = {10.1007/s10570-026-06963-y}, author = {Rajput, Tejas and Sathe, Asmi and Gopal, Animesh and Sharma, Aakash and Shanmuganathan, Kadhiravan} }