Supplementary MaterialsSupplementary Data. inside a repeatable and reproducible way. The thickness from the PEGDA microstructures was controllable from 15 to 300 = 15, 10 and 5 cm). The result of spacer thickness for the quality of PEGDA micropatterns was researched with a photomask patterned with 200 = 15), = 100), em /em m /th /thead Polyethylene cover film14.3 5.115.8 5.3Aluminum foil18 1.728.1 5.4Scotch tape48.8 2.061.2 2.7Coverslip155 1.6148 9.4Two coverslips311 2.9269 11 Open up in another window The perfect UV condition and resulting relative design size had been 14.2 mJ cm?2 and 103.4 18.4% for 100 em /em m. For 200 em /em m and 500 em /em m width face mask patterns, the assessed design sizes at the perfect UV energy with 53.4 mJ cm?2 were 91.5 5.7% and 97.4 2.8%, respectively (figure 2( em b /em )). Shape 2( em c /em ) displays the result of elevation for the PEGDA design size under different UV energy circumstances. In these tests, the photomask design width was set to 200 em /em m as well as the UV energy was transformed (6.47, 14.2 and 53.4 mJ cm?2). For circumstances where the PEGDA micromold elevation was 50 em /em m, the width from the polymerized PEGDA grooves reduced from 131 4.45% to 92.5 11.3% of how big is the photomask patterns as the UV energy was increased from 6.47 mJ cm?2 to 53.4 mJ cm?2. This means that that, needlessly to say, the amount of polymerization improved with lighted UV energy, producing a reduction in the PEGDA groove width as demonstrated in shape 2( em e /em ). UV energy for patterning could be transformed relating to different photoinitiator focus (supplementary picture S1 obtainable from stacks.iop.org/BF/2/045001/mmedia). The UV publicity period for the same-sized design was reduced as photoinitiator focus increased. To get a photomask having a 320 em /em m width and 150 em /em m width spacer, shorter publicity time led to bigger groove width reflecting insufficient crosslinking for many photoinitiator concentrations. 3.2. Balance of PEGDA get better at molds PEGDA get better at molds had been steady without changing their constructions for the TMSPMA-coated substrates and were resistant to wear after multiple rounds of replications with PDMS. The acrylic functional group Slco2a1 of TMSPMA on the substrates and PEGDA were crosslinked during UV exposure, which enhanced the stability of polymerized PEGDA on glass substrates (figure 3( em order BMS-790052 a /em )). Acrylation of the substrates with TMSPMA improved adhesion and stabilized the micropattern layer on the glass as well as Si wafers . In contrast, PEGDA layers formed order BMS-790052 on non-treated glass substrates were easily detached from the substrate during drying and PDMS curing processes (figure 3( em b /em )). Open in a separate window Figure 3 ( em a /em ) UV crosslinking of PEGDA with surface bound TMSPMA. ( em b /em ) Delamination of PEGDA micromolds from the bare glass surface. Low molecular weight (LMW) PEGDA with 258 Da was more stable for micropatterning compared to high molecular weight (HMW) PEGDA. HMW PEGDA (over 1000 Da) structures, both under hydrated and dehydrated conditions, were easily detached from the substrates. This was partially due to the swelling of order BMS-790052 the structures during washing processes. In contrast, LMW PEGDA (under 1000 Da) did not show significant swelling or shrinking during development and PDMS curing steps. The PDMS microfluidic pattern replicated from PEGDA micromolds did not show a order BMS-790052 significant difference in function compared to conventional photoresist-based products. In addition, PEGDA replicated PDMS structures could be plasma treated for adhesion to glass surfaces similar to PDMS cured on the Si wafer. These microstructures could be used to generate microfluidic channels capable of generating concentration gradients with.