Fig. 2. BTA modular mixing allows for tuning of the viscoelastic properties of hydrogels: (A) BTA (100 : 0, in grey) and BTA-PEG-BTA (0 : 100 in black) storage moduli (filled symbol) and loss moduli (empty symbol) as a function of frequency. (B) The tuning of the storage moduli by copolymerisation of BTA and BTA-PEG-BTA. (C) The tan δ (G′′/G′) as a function of frequency of the copolymerised hydrogels. (D) The stress relaxation profiles of the hydrogels when subjected to constant 1% strain. Duplicates were performed for all the hydrogel formulations in A, B, and C. Similar trends in viscoelasticity were found, and the tan δ (G′′/G′) values are reported for all runs in the ESI Fig S3E.† Duplicates were performed for 25 : 75 (BTA : BTA-PEG-BTA) in D in order to confirm the outlier behaviour and are reported in Fig. S4C.†.