Process optimization and optimal tolerancing to improve dimensional accuracy of vat-photopolymerized functionally graded hydrogels

Hisham, Muhammed; Kumar, Girish; Deshpande, Abhijit P.

doi:10.1016/j.rineng.2022.100442

Cited by 10 publications

(12 citation statements)

References 36 publications

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“…In the 10 mm wide sample, the difference in width between sections was still visible but comparatively less apparent. Previous studies have shown that the change in the lateral dimension that occurs with material change is a constant change at the edges of the sample, independent of sample dimension . Thus, the same difference in width would occur at the edges for 2 and 10 mm wide samples, which makes the difference less apparent in 10 mm wide samples.…”

Section: Resultsmentioning

confidence: 97%

“…Previous studies have shown that the change in the lateral dimension that occurs with material change is a constant change at the edges of the sample, independent of sample dimension. 28 Thus, the same difference in width would occur at the edges for 2 and 10 mm wide samples, which makes the difference less apparent in 10 mm wide samples. Although an interface discontinuity is still present in the central portion of the 10 mm wide samples, it appears more uniform.…”

Section: Resultsmentioning

confidence: 99%

“…This method has also been used in some studies as it is economical and feasible, although a manual intervention is necessary. 15,28 Studies on using multimaterial 3D printing of optical applications (such as multimaterial and functionalized contact lenses) have been rather limited. Joralmon et al 19 used multimaterial DLP printing to produce liquid crystals that change optical properties with temperature.…”

Section: Introductionmentioning

confidence: 99%

“…These issues also limit the production of multimaterial objects with complex patterns. These challenges include the formation of an interface at the point of a material change, the change in lateral dimensions with material change, and difficulty in producing variations in the lateral ( x – y ) plane. , Previous studies have shown that lateral deviations can be resolved by suitable CAD model correction . However, there are no studies which sufficiently address the other two challenges.…”

Section: Introductionmentioning

confidence: 99%

“…A more straightforward method for producing multimaterial parts with commercially available DLP printers is to pause the printer when required and manually change the material in the vat (Figure a). This method has also been used in some studies as it is economical and feasible, although a manual intervention is necessary. , …”

Section: Introductionmentioning

confidence: 99%

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3D Printing of Multimaterial Contact Lenses

Hisham

Salih

Butt

2023

ACS Biomater. Sci. Eng.

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3D printing of multimaterial objects is an emerging field with promising applications. The layer-by-layer material addition technique used in 3D printing enables incorporation of distinct functionalized materials into the specialized devices. However, very few studies have been performed on the usage of multimaterial 3D printing for printable photonic and wearable devices. Here, we employ vat photopolymerization-based 3D printing to produce multimaterial contact lenses, offering enhanced multiband optical filtration, which can be valuable for tackling ocular conditions such as color blindness. A combination of hydroxyethyl methacrylate (HEMA) and polyethylene glycol diacrylate (PEGDA) was used as the base hydrogel for 3D printing. Atto565 and Atto488 dyes were added to the hydrogel for wavelength filtering, each dye suitable for a different type of color blindness. Multimaterial disks and contact lenses, with separate sections containing distinct dyes, were 3D-printed, and their optical properties were studied. The characteristics of multimaterial printing were analyzed, focusing on the formation of a uniform multimaterial interface. In addition, a novel technique was developed for printing multiple dyed materials in complex lateral geometrical patterns, by employing suitable variations in CAD models and the UV curing time. It was observed that the multimaterial printing process does not negatively affect the optical properties of the contact lenses. The printed multimaterial contact lenses offered a combined multi-band color blindness correction due to the two dyes used. The resulting optical spectrum was a close match to the commercially available color blindness correction glasses.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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3D Printing of Multimaterial Contact Lenses

Hisham

Salih

Butt

2023

ACS Biomater. Sci. Eng.

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Engineered Living Material Bioreactors with Tunable Mechanical Properties using Vat Photopolymerization

Altin‐Yavuzarslan,

Sadaba,

Brooks

et al. 2023

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Abstract3D‐printed engineered living materials (ELM) are promising bioproduction platforms for agriculture, biotechnology, sustainable energy, and green technology applications. However, the design of these platforms faces several challenges, such as the processability of these materials into complex form factors and control over their mechanical properties. Herein, ELM are presented as 3D‐printed bioreactors with arbitrary shape geometries and tunable mechanical properties (moduli and toughness). Poly(ethylene glycol) diacrylate (PEGDA) is used as the precursor to create polymer networks that encapsulate the microorganisms during the vat photopolymerization process. A major limitation of PEGDA networks is their propensity to swell and fracture when submerged in water. The authors overcame this issue by adding glycerol to the resin formulation to 3D print mechanically tough ELM hydrogels. While polymer concentration affects the modulus and reduces bioproduction, ELM bioreactors still maintain their metabolic activity regardless of polymer concentration. These ELM bioreactors have the potential to be used in different applications for sustainable architecture, food production, and biomedical devices that require different mechanical properties from soft to stiff.

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