scholarly journals Cationic Cellulose Nanocrystals-Based Nanocomposite Hydrogels: Achieving 3D Printable Capacitive Sensors with High Transparency and Mechanical Strength

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 688
Author(s):  
Po-Cheng Lai ◽  
Sheng-Sheng Yu
Keyword(s):  
3D Printing ◽  
Surface Chemistry ◽  
Mechanical Strength ◽  
Cellulose Nanocrystals ◽  
Soft Materials ◽  
Capacitive Sensors ◽  
Wearable Electronics ◽  
High Transparency ◽  
Physical Network ◽  
Nanocomposite Hydrogels

Hydrogel ionotronics are intriguing soft materials that have been applied in wearable electronics and artificial muscles. These applications often require the hydrogels to be tough, transparent, and 3D printable. Renewable materials like cellulose nanocrystals (CNCs) with tunable surface chemistry provide a means to prepare tough nanocomposite hydrogels. Here, we designed ink for 3D printable sensors with cationic cellulose nanocrystals (CCNCs) and zwitterionic hydrogels. CCNCs were first dispersed in an aqueous solution of monomers to prepare the ink with a reversible physical network. Subsequent photopolymerization and the introduction of Al3+ ion led to strong hydrogels with multiple physical cross-links. When compared to the hydrogels using conventional CNCs, CCNCs formed a stronger physical network in water that greatly reduced the concentration of nanocrystals needed for reinforcing and 3D printing. In addition, the low concentration of nanofillers enhanced the transparency of the hydrogels for wearable electronics. We then assembled the CCNC-reinforced nanocomposite hydrogels with stretchable dielectrics into capacitive sensors for the monitoring of various human activities. 3D printing further enabled a facile design of tactile sensors with enhanced sensitivity. By harnessing the surface chemistry of the nanocrystals, our nanocomposite hydrogels simultaneously achieved good mechanical strength, high transparency, and 3D printability.

All-in-One Cellulose Nanocrystals for 3D Printing of Nanocomposite Hydrogels

2018 ◽  
Vol 130 (9) ◽  
pp. 2377-2380 ◽  
Author(s):  
Jieping Wang ◽  
Annalisa Chiappone ◽  
Ignazio Roppolo ◽  
Feng Shao ◽  
Erika Fantino ◽  
...  
Keyword(s):  
3D Printing ◽  
Cellulose Nanocrystals ◽  
Nanocomposite Hydrogels

All-in-One Cellulose Nanocrystals for 3D Printing of Nanocomposite Hydrogels

2018 ◽  
Vol 57 (9) ◽  
pp. 2353-2356 ◽  
Author(s):  
Jieping Wang ◽  
Annalisa Chiappone ◽  
Ignazio Roppolo ◽  
Feng Shao ◽  
Erika Fantino ◽  
...  
Keyword(s):  
3D Printing ◽  
Cellulose Nanocrystals ◽  
Nanocomposite Hydrogels

Role of in situ added cellulose nanocrystals as rheological modulator of novel waterborne polyurethane urea for 3D-printing technology

Cellulose ◽  
2021 ◽  
Author(s):  
Julen Vadillo ◽  
Izaskun Larraza ◽  
Tamara Calvo-Correas ◽  
Nagore Gabilondo ◽  
Christophe Derail ◽  
...  
Keyword(s):  
3D Printing ◽  
Cellulose Nanocrystals ◽  
Waterborne Polyurethane ◽  
Printing Technology ◽  
3D Printing Technology

Surface Chemistry and Characterization of Cellulose Nanocrystals

2018 ◽  
pp. 223-252 ◽  
Author(s):  
Samuel Eyley ◽  
Christina Schütz ◽  
Wim Thielemans
Keyword(s):  
Surface Chemistry ◽  
Cellulose Nanocrystals

scholarly journals Printable Alginate Hydrogels with Embedded Network of Halloysite Nanotubes: Effect of Polymer Cross-Linking on Rheological Properties and Microstructure

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4130
Author(s):  
Svetlana A. Glukhova ◽  
Vyacheslav S. Molchanov ◽  
Boris V. Lokshin ◽  
Andrei V. Rogachev ◽  
Alexey A. Tsarenko ◽  
...  
Keyword(s):  
3D Printing ◽  
Rheological Properties ◽  
Shear Thinning ◽  
Halloysite Nanotubes ◽  
Polymer Chains ◽  
Cross Linking ◽  
Saxs Data ◽  
Nanocomposite Hydrogels ◽  
Embedded Network ◽  
The Cross

Rapidly growing 3D printing of hydrogels requires network materials which combine enhanced mechanical properties and printability. One of the most promising approaches to strengthen the hydrogels consists of the incorporation of inorganic fillers. In this paper, the rheological properties important for 3D printability were studied for nanocomposite hydrogels based on a rigid network of percolating halloysite nanotubes embedded in a soft alginate network cross-linked by calcium ions. Particular attention was paid to the effect of polymer cross-linking on these properties. It was revealed that the system possessed a pronounced shear-thinning behavior accompanied by a viscosity drop of 4–5 orders of magnitude. The polymer cross-links enhanced the shear-thinning properties and accelerated the viscosity recovery at rest so that the system could regain 96% of viscosity in only 18 s. Increasing the cross-linking of the soft network also enhanced the storage modulus of the nanocomposite system by up to 2 kPa. Through SAXS data, it was shown that at cross-linking, the junction zones consisting of fragments of two laterally aligned polymer chains were formed, which should have provided additional strength to the hydrogel. At the same time, the cross-linking of the soft network only slightly affected the yield stress, which seemed to be mainly determined by the rigid percolation network of nanotubes and reached 327 Pa. These properties make the alginate/halloysite hydrogels very promising for 3D printing, in particular, for biomedical purposes taking into account the natural origin, low toxicity, and good biocompatibility of both components.

Smart and Connected Bioelectronics for Seamless Health Monitoring and Persistent Human-Machine Interfaces

2018 ◽  
Vol 2018 (1) ◽  
pp. 000660-000664 ◽  
Author(s):  
Yun-Soung Kim ◽  
Woon-Hong Yeo
Keyword(s):  
Health Monitoring ◽  
Information Science ◽  
Wearable Sensors ◽  
Soft Materials ◽  
Electronic Systems ◽  
Wearable Electronics ◽  
Prosthetic Hands ◽  
Computer Interfaces ◽  
Human Machine Interfaces ◽  
Rapid Transformation

Abstract Recent advancement of flexible wearable electronics allows significant enhancement of portable, continuous health monitoring and persistent human-machine interfaces. Enabled by flexible electronic systems, smart and connected bioelectronics are accelerating the integration of innovative information science and engineering strategies, ultimately driving the rapid transformation of healthcare and medicine. Recent progress in development and engineering of soft materials has provided various opportunities to design different types of mechanically deformable systems towards smart and connected bioelectronics. Here, we summarize the key properties of soft materials and their characteristics in the context of wearable sensors and electronics. Details of functionality and sensitivity of the bioelectronics are discussed with applications in health, medicine, and machine interfaces. In addition, we introduce recent examples of bioelectronics that offer persistent human-machine interfaces to control prosthetic hands, wheelchairs, or computer interfaces.

Effects of post-curing conditions on mechanical properties of 3D printed clear dental aligners

2020 ◽  
Vol 26 (8) ◽  
pp. 1337-1344 ◽  
Author(s):  
Prashant Jindal ◽  
Mamta Juneja ◽  
Divya Bajaj ◽  
Francesco Luke Siena ◽  
Philip Breedon
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Mechanical Strength ◽  
Financial Burden ◽  
Experimental Studies ◽  
Cost Savings ◽  
Time Duration ◽  
Content Type ◽  
Curing Conditions ◽  
3D Printed

Purpose 3D printing techniques have been widely used for manufacturing complex parts for various dental applications. For achieving suitable mechanical strength, post-cure processing is necessary, where the relative time duration and temperature specification also needs to be defined. The purpose of this study/paper is to assess the effects of post curing conditions and mechanical properties of 3D printed clear dental aligners Design/methodology/approach Dental long-term clear resin material has been used for 3D printing of dental aligners using a Formlabs 3D printer for direct usage on patients. Post-curing conditions have been varied, all of which have been subjected to mechanical compression loading of 1,000 N to evaluate the curing effects on the mechanical strength of the aligners. Findings The experimental studies provide significant insight into both temperatures and time durations that could provide sufficient compressive mechanical strength to the 3D printed clear dental aligners. It was observed that uncured aligners deformed plastically with large deformations under the loading conditions, whereas aligners cured between 400°C–800°C for 15–20 min deformed elastically before fragmenting into pieces after safely sustaining higher compressive loads between 495 N and 666 N. The compressive modulus ratio for cured aligners ranged between 4.46 and 5.90 as compared to uncured aligners. For shorter cure time durations and lower temperature conditions, an appropriate elevated compressive strength was also achieved. Originality/value Based on initial assessments by dental surgeons, suitable customised clear aligners can be designed, printed and cured to the desired levels based on patient’s requirements. This could result in time, energy and unit production cost savings, which ultimately would help to alleviate the financial burden placed on both the health service and their patients.

scholarly journals Highly conductive carbon-based aqueous inks toward electroluminescent devices, printed capacitive sensors and flexible wearable electronics

RSC Advances ◽  
2019 ◽  
Vol 9 (27) ◽  
pp. 15184-15189 ◽  
Author(s):  
Yu Liao ◽  
Rui Zhang ◽  
Hongxia Wang ◽  
Shuangli Ye ◽  
Yihua Zhou ◽  
...  
Keyword(s):  
Capacitive Sensors ◽  
Wearable Electronics ◽  
Electroluminescent Devices ◽  
Conductive Inks ◽  
Carbon Based

Carbon-based conductive inks are one of the most important materials in the field of printing electronics.

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