College of Engineering and Polymer Science

Date of Last Revision

2023-05-08 15:56:53


Chemical Engineering

Honors Course

CHEE 497-001

Number of Credits


Degree Name

Bachelor of Science

Date of Expected Graduation

Spring 2023


Three polyethylene glycol (PEG) based crosslinkers with repeat unit nominal weights of 62.1, 200, and 400 g/mol in agar/PAM double network (DN) hydrogels were used to study the effect of different crosslinkers on thermal and mechanical properties. Using the one-pot synthesis method, hydrogels with the PEG crosslinkers or methylene-bis-acrylamide (MBAA) were made via sol-gel transition for formation of agar network, and photopolymerization of the PAM network using Irgacure 2959 as photo initiator. Tensile and compression tests were performed on as prepared, swollen, and swollen & cooled specimens of each hydrogel. Freezing time and thermal imaging were performed in -20 °C freezer, and thawing at room temperature followed freezing in -60 °C freezer. MBAA then PEG based crosslinkers with increasing molecular weight increased freezing time (normalized 1 hr, 1.9 hr, 2.9 hr, 3.8 hr) and decreased heat conductivity which may result from London dispersion forces, crosslinker hydrogen bonds with water, and porosity. Under tension and compression, PEG400-INA and EGINA based crosslinker experienced better trends from colder temperatures on mechanical properties than MBAA. They also experienced decreased swelling ratios of 6.11, 5.65, 5.20, 5.75 from MBAA to PEG400-INA when compared to that of PAM SN 11.69. This is work will inspire researchers to optimize PEG based crosslinkers in as prepared hydrogels, understand their anti-freezing mechanisms, and find applications in low temperature environments such as supercapacitors, and deep ocean.

Research Sponsor

Dr. Jie Zheng

First Reader

Dr. James Eagan

Second Reader

Dr. Donald P. Visco Jr.

Honors Faculty Advisor

Dr. Donald P. Visco Jr.

Proprietary and/or Confidential Information


Gross-HonorsProjectSignatures (002).pdf (385 kB)
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