## 3 Results and Discussion  
### Solvent Resistance of Nanoimprint Resist Materials  
TPULR9, TPULR4.5, and TPULR0 must have the UV polymerizable property and solvent resistance in order to achieve the excellent patterning dimensional accuracy. The evaluation of solvent resistance using ethyl lactate showed no detectable changes in film thickness, indicating that TPULR9, TPULR4.5, and TPULR0 do not significantly interact. It was obvious that TPULR9, TPULR4.5, and TPULR0 were polymerized on the basis of their solvent resistance.  
\begin{table}
\begin{tabular}{l c c c c} \hline
**Liquid** & \(\gamma_{\rm L}\) & \(\gamma_{\rm L}^{\rm d}\) & \(\gamma_{\rm L}^{\rm p}\) & \(\gamma_{\rm L}^{\rm h}\) \\ \hline Water & 72.8 & 29.1 & 1.3 & 42.4 \\ n-Hexadecane & 27.6 & 27.6 & 0.0 & 0.0 \\ Diiodomethane & 50.8 & 46.8 & 4.0 & 0.0 \\ \hline \end{tabular}
\end{table}
Table 2: Surface free energy components of water, n-hexadecane, and diiodomethane: \(\gamma_{\rm L}\) surface free energy, \(\gamma_{\rm L}^{\rm d}\) dispersive component, \(\gamma_{\rm L}^{\rm p}\) polar component, and \(\gamma_{\rm L}^{\rm h}\) hydrogen-bonded component.  
Effect of Surface Free Energy of Nanoimprint Resist Materials Containing a UV Reactive Fluorine Surfactant on Defect Reduction in Nanoimprint Patterning Replication  
Table 3 shows the calculated surface free energy components of TPULR9, TPULR4.5, and TPULR0 with different concentrations of UV reactive fluorine surfactant.  
The surface free energy of TPULR9, TPULR4.5, and TPULR0 were determined as 22, 20 and 47, respectively. TPULR4.5 and TPULR9 containing 4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11, 11-heptadecafluoro-2-hydroxyundecyl acrylate showed a better range of surface free energy than TPULR0. This was because the surface free energy in the nanoimprint resist materials was considered to be related to the rounding of sharp corners due to the surface free energy after the template was released from the surface of the nanoimprinted resist material on the template. Therefore, the reduction of the surface free energy in TPULR4.5 and TPULR9 was expected to lead to stronger anti-adhesion. The surface free energy and the components were related to the concentration of 4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,11-heptadecafluoro-2-hydroxyundecyl acrylate as shown in Table 1.  
The surface free energy and the components decreased generally as the concentration of the prepared UV reactive fluorine surfactant in the resist material increased. In the material combination of the developed resist TPULR4.5 and TPULR9 on underlayer TPUL-UL, it was not possible to find the significant difference of surface energy value between 4.5 wt% and 9 wt%, as the concentration of the UV reactive fluorine surfactant increases more than 4.5 wt%. In order to investigate the cause of the observed relationship between surface energy value and materials, the influences such as UV cross-link reaction ratio, the surface energy value of the underlayer, phase separation, and micro-morphology were considered. The optimized concentration was found to be 4.5 wt%, in order to develop the new nanoimprint resist with great repeatability and durability of the nanoimprint processes. Therefore, TPULR4.5 was used in this study being acceptable for the evaluation of repeatability and durability of nanoimprint processes.