title: A method for an approximate determination of a polymer-rich-domain concentration in phase-separated poly(N-isopropylacrylamide) aqueous solution by means of confocal Raman microspectroscopy combined with optical tweezers.
abstract: The paper demonstrates that a confocal Raman microspectroscope combined with optical tweezers is a promising technique to estimate polymer concentration in polymer-rich domain in phase-separated-aqueous polymer solution. The sample polymer is poly-(N-isopropylacrylamide) (PNIPAM) that is well-known as a representative thermo-responsive polymer. Optical tweezers can selectively trap the polymer-rich domain at the focal point in non-contact and non-intrusive modes. Such situation allows us to determine polymer concentration in the domain, which has been unclear due to a lack of appropriate analytical technique. It is applicable for a variety of other thermo-responsive polymers.
authors.affiliation: Division of Molecular Materials Science, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka 558-8585, Japan. Electronic address: t-shoji@sci.osaka-cu.ac.jp.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Shoji
authors.affiliation: Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-0810, Japan.
authors.forename: Riku
authors.initials: R
authors.lastname: Nohara
authors.affiliation: Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-0810, Japan; Department of Chemistry, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan.
authors.forename: Noboru
authors.initials: N
authors.lastname: Kitamura
authors.affiliation: Division of Molecular Materials Science, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka 558-8585, Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Tsuboi
keywords: Confocal Raman microspectroscopy; Near-infrared laser beam; Optical trapping; Optical tweezers; Photothermal effect; Poly-(N-isopropylacrylamide); Radiation force; Thermo-responsive polymer