Double-Network Hydrogel-Based Photonic Crystal Sensor for Mechanical Force Naked Eye Sensing and Its Application in Medical Compressive or Stretchy Instruments

Abstract

Herein, we coalesced a poly(acrylamide-co-N-Acryloyl phenylalanine)/polyacrylamide double-network (P(AMco-APA)/PAM DN) hydrogel with a photonic crystal array, fabricating a mechanochromic sensor for application in flexible medical instruments by naked eye monitoring. The intensified mechanical properties of the DN hydrogel were proved by the mechanical property tests, which are attributed to the interactions of chemical bonds and hydrogen bonds between the two polymer networks. In the range of stress from 0 to 328 kPa, the reflected light wavelength of this sensor changed from 659 to 480 nm and the color changed from red to blue in response; in the range of pressure from 0 to 85 kPa, the sensor exhibited a spectrum changing from 658 nm to 467 nm, covering almost the whole visible color range. The prepared sensor was incorporated into medical instruments including the femoral artery hemostat and bandage to indicate pressure and tensile stress in practical applications. Within the appropriate pressure for wound recovery, the sensitivity and correlation between the external stimulus of pressure and wavelength of this integrated sensor were 5.58 nm•kPa −1 and over 0.99, respectively. Ultimately, the sensor proved to be tough, sensitive, and durable, showing a broad prospect of a series of future applications.

Biomimetic photonic crystal double-network hydrogel for visual and electrical dual signal bluetooth-enabled wearable sensor

“…S13, ESI †). Compared with previous reports, [28][29][30]46,47 the PC wearable sensors exhibited significantly comprehensive performances (Fig. 6e).…”

“…For example, Liu et al designed a PC sensor by combining DNHs and polystyrene (PS) photonic crystal arrays, which were applied to human stretchable instruments. 28 As reported by Liu and co-workers, a PC wearable strain sensor based on hydrogels was synthesized and showed fantastic color change and electronic sensing signals under different strains. 29 The biomimetic PC wearable sensors output splendid optical signals that are captured directly by the naked eye and exhibit remarkable merits, including rapid response, reversible color response, low-cost, and facile manufacturing.…”

Anisotropic Bi-Layer Hydrogel Actuator with pH-Responsive Color-Changing and Photothermal-Responsive Shape-Changing Bi-Functional Synergy

“…Nowadays, many color-changing hydrogels have been developed, which can provide good detection in diverse fields, such as heavy metal sensing, biomedicine, intelligent displaying, and so on. There are several main kinds of color-changing hydrogels based on different mechanisms, including (1) traditional organic molecules/polymers with fluorescent groups with aggregation-caused quenching (ACQ) effect [ 7 , 8 , 9 ]; (2) recent organic molecules/polymers with aggregation-induced emission (AIE) effect [ 10 , 11 , 12 , 13 , 14 , 15 ]; (3) various luminescent nanoparticles (such as fluorescent carbon dots [ 16 , 17 , 18 ], photonic crystals [ 19 , 20 , 21 ], and quantum dots [ 22 , 23 , 24 ]).…”