Dual-Responsive Hydrogels for Direct-Write 3D Printing

2015 ◽  
Vol 48 (18) ◽  
pp. 6482-6488 ◽  
Author(s):  
Musan Zhang ◽  
Ankit Vora ◽  
Wei Han ◽  
Rudy J. Wojtecki ◽  
Hareem Maune ◽  
...  
2021 ◽  
pp. 002199832110022
Author(s):  
Ahmed Alhelal ◽  
Zaheeruddin Mohammed ◽  
Shaik Jeelani ◽  
Vijaya K Rangari

Semi-crystalline carbon biochar is derived from spent coffee grounds (SCG) by a controlled pyrolysis process at high temperature/pressure conditions. Obtained biochar is characterized using XRD, SEM, and TEM techniques. Biochar particles are in the micrometer range with nanostructured morphologies. The SCG biochar thus produced is used as reinforcement in epoxy resin to 3 D print samples using the direct-write (DW) method with 1 and 3 wt. % loadings. Rheology results show that the addition of biochar makes resin viscous, enabling it to be stable soon after print; however, it could also lead to clogging of resin in printer head. The printed samples are characterized for chemical, thermal and mechanical properties using FTIR, TGA, DMA and flexure tests. Storage modulus improved with 1 wt. % biochar addition up to 27.5% and flexural modulus and strength increased up to 55.55% and 43.30% respectively. However, with higher loading of 3 wt. % both viscoelastic and flexural properties of 3D printed samples drastically reduced thus undermining the feasibility of 3D printing biochar reinforced epoxies at higher loadings.


2020 ◽  
pp. 2000070
Author(s):  
Taylor V. Neumann ◽  
Michael D. Dickey

2019 ◽  
Vol 6 (8) ◽  
pp. 085319
Author(s):  
Bijan Nasri-Nasrabadi ◽  
Akif Kaynak ◽  
Scott D Adams ◽  
Pejman Heidarian ◽  
Abbas Z Kouzani

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2204
Author(s):  
Zhidan Wang ◽  
Jie Wu ◽  
Xiaoyu Shi ◽  
Fei Song ◽  
Wenli Gao ◽  
...  

Physical crosslinking and chemical crosslinking were used to further improve the mechanical properties and stability of the gel. A temperature/pH dual sensitive and double-crosslinked gel was prepared by the stereo-complex of HEMA-PLLA20 and HEMA-PDLA20 as a physical crosslinking agent, ethylene glycol dimethacrylate (EGDMA) as a chemical crosslinking agent, and azodiisobutyronitrile (AIBN) as an initiator for free radical polymerization. This paper focused on the performance comparison of chemical crosslinked gel, a physical crosslinked gel, and a dual crosslinked gel. The water absorption, temperature, and pH sensitivity of the three hydrogels were studied by a scanning electron microscope (SEM) and swelling performance research. We used a thermal analysis system (TGA) and dynamic viscoelastic spectrometer to study thermal properties and mechanical properties of these gels. Lastly, the in vitro drug release behavior of double-crosslinked hydrogel loaded with doxorubicin under different conditions was studied. The results show that the double-crosslinked and temperature/pH dual responsive hydrogels has great mechanical properties and good stability.


2020 ◽  
Vol 6 (24) ◽  
pp. eaaz7202 ◽  
Author(s):  
Bijal B. Patel ◽  
Dylan J. Walsh ◽  
Do Hoon Kim ◽  
Justin Kwok ◽  
Byeongdu Lee ◽  
...  

Additive manufacturing of functional materials is limited by control of microstructure and assembly at the nanoscale. In this work, we integrate nonequilibrium self-assembly with direct-write three-dimensional (3D) printing to prepare bottlebrush block copolymer (BBCP) photonic crystals (PCs) with tunable structure color. After varying deposition conditions during printing of a single ink solution, peak reflected wavelength for BBCP PCs span a range of 403 to 626 nm (blue to red), corresponding to an estimated change in d-spacing of >70 nm (Bragg- Snell equation). Physical characterization confirms that these vivid optical effects are underpinned by tuning of lamellar domain spacing, which we attribute to modulation of polymer conformation. Using in situ optical microscopy and solvent-vapor annealing, we identify kinetic trapping of metastable microstructures during printing as the mechanism for domain size control. More generally, we present a robust processing scheme with potential for on-the-fly property tuning of a variety of functional materials.


2013 ◽  
Vol 20 (10) ◽  
Author(s):  
Abbas Khan ◽  
Muhammad Bisyrul Hafi Othman ◽  
Khairunisak Abdul Razak ◽  
Hazizan Md Akil

2021 ◽  
pp. 102419
Author(s):  
Nava Raj Khatri ◽  
Md. Nurul Islam ◽  
Peng-Fei Cao ◽  
Rigoberto C. Advincula ◽  
Wonbong Choi ◽  
...  

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