Interpenetrating interfaces between a deuterated polystyrene (dPS) and the grafted substrates with the same chemical identity were characterized using neutron reflectivity (NR) measurements, where the PS-grafted substrates were prepared using a grafting-to approach with hydroxyl end-functionalized polystyrene (PSOH) in a dry brush regime. The characteristic brush thickness (h) and grafting density (σ) of PS-grafted layers were determined based on the chain length (or molecular weight, Mn) of PSOHs. The experimental interpenetration length (ξ) was measured at the interfaces, and the limiting plateau in ξ above which the value was independent of film thickness shifted toward higher values as the Mn of PSOH increased. Normalization by the deformed brush thickness (hd) of PS-grafted layer after interpenetration revealed that the experimental value of ξ/hd in a short and dense PS-grafted substrate, prepared with a low-molecular-weight PSOH, deviated markedly from the theoretical value, indicating significant additional stretching of the grafted chains to accommodate inter-mixing with the dPS chains.
Bibliographical noteFunding Information:
This work was supported by the NRF grants ( 2014R1A2A2A01004364 ), Nuclear R&D Programs, and APCPI ERC ( 2007-0056091 ) funded by the Ministry of Science, ICT & Future Planning (MSIP), Korea . This work was also supported by Grant-in-Aid for the Scientific Research (A) ( 15H02183 ) from the Ministry of Education, Culture, Sports, Science, and Technology, Japan. NR experiment was supported by the Neutron Scattering Program Advisory of IMSS, KEK ( 2009S08 ).
All Science Journal Classification (ASJC) codes
- Organic Chemistry
- Polymers and Plastics
- Materials Chemistry