Authors: Tsuneo Okubo Akira Hagiwara Hiromi Kitano Shinya Takahashi Akira Tsuchida
Publish Date: 2015/04/28
Volume: 293, Issue: 8, Pages: 2137-2146
Abstract
Drying patterns of polymethacrylic acid HPMA and its salt neutralized half with sodium hydroxide NaHPMA were studied on a cover glass a watch glass and a glass dish The patterns of HPMA and NaHPMA are compared with the previous observation of sodium salt of polymethacrylic acid NaPMA Okubo et al Colloid Polym Sci 2871155–1165 2009 HPMA and especially NaHPMA are hygroscopic and only the macroscopic patterns were observed However microscopic patterns were not observed clearly especially for NaHPMA in the room atmosphere The hygroscopy of the dried films was in the order NaPMA HPMA NaHPMA Broad rings of HPMA formed only at the outside edge irrespective of polymer concentration Simplified laurel crownlike patterns appeared on a cover glass which supports the strong solute–substrate affinity On the other hand the broad ring size of NaHPMA decreased sharply at the lower polymer concentrations than the critical concentration m The results of NaHPMA support that both the intersolutes and solute–substrate affinity are rather weak and the pattern size was determined with the excluded volume effects Sharpness parameter S of the broad rings was in the order HPMA NaHPMA NaPMA The magnitude of S values of NaPMA was similar to that of polyethylene glycol PEG HPMA NaHPMA and NaPMA were grouped into E A and A respectively among six groups of solutes A to F
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