Chitosan-based hydrogels: A new polymer-based system with excellent laser-damage threshold properties

Abstract

Two types of chitosan hydrogel systems have been prepared that have a laser damage threshold (LDT) up to 35 times higher than commercial PMMA bulk materials. For these samples, the LDT increases with increasing water content. The mechanism of laser damage and the contribution of water to their high laser damage resistance have been examined. DSC measurements indicate water within the hydrogels exist in various states, each with different laser damage resistance properties. These various states play a key role in determining the LDT by controlling the dissipation of laser energy and providing a mechanism for self‐healing. This preliminary research shows that polymer hydrogels have potential for high power laser applications because they combine good mechanical integrity due to the polymer frame and good energy dissipation and healing characteristics due to the molecular mobility of water. These two traits allow for bulk shape‐retaining films with high laser damage thresholds and potential reversibility in damage processes. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 769–778, 1999

Rheology of highly swollen chitosan/polyacrylate hydrogels

“…Many attempts have been made to improve the laser damage resistance of polymer materials in the last two decades [11][12][13]. Recently, our lab reported that hydrogel systems based on chitosan polymers have emerged as a new class of host materials for laser applications [14,15]. These chitosan hydrogel systems show excellent laser damage thresholds (LDT) of 290-450 mJ, 20 to 35 times higher than that of commercial PMMA (16 mJ).…”

“…Different temperature and frequency sweeps were performed in an attempt to further understand the relationship between the structure and properties. These results are compared to the conclusions made in our recent studies using DSC measurements [15] with regard to the high LDT observed.…”

“…Details about the chemistry and basic characterization as well as the general procedures for preparation of the chitosan hydrogel system can be obtained in Ref. [15]. The water content was measured gravimetrically by vacuum drying (GVD).…”

“…These chitosan hydrogel systems show excellent laser damage thresholds (LDT) of 290-450 mJ, 20 to 35 times higher than that of commercial PMMA (16 mJ). The measured LDT is also substantially better than BK7 glass (68 mJ) and optical grade quartz (272 mJ), widely used inorganic optical materials [15], when tested in identical experimental configurations.…”

“…These gel systems are considered crosslinked macromolecular networks which form a heterogeneous microporous structure holding a large amount of water [15]. This water has been shown to be either bound in part by hydrophilic interactions with the internal polymer surfaces or associated to different degrees depending on the internal structure.…”