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Flemming P, Münch AS, Fery A, Uhlmann P. Constrained thermoresponsive polymers - new insights into fundamentals and applications. Beilstein J Org Chem 2021; 17:2123-2163. [PMID: 34476018 PMCID: PMC8381851 DOI: 10.3762/bjoc.17.138] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 08/10/2021] [Indexed: 12/15/2022] Open
Abstract
In the last decades, numerous stimuli-responsive polymers have been developed and investigated regarding their switching properties. In particular, thermoresponsive polymers, which form a miscibility gap with the ambient solvent with a lower or upper critical demixing point depending on the temperature, have been intensively studied in solution. For the application of such polymers in novel sensors, drug delivery systems or as multifunctional coatings, they typically have to be transferred into specific arrangements, such as micelles, polymer films or grafted nanoparticles. However, it turns out that the thermodynamic concept for the phase transition of free polymer chains fails, when thermoresponsive polymers are assembled into such sterically confined architectures. Whereas many published studies focus on synthetic aspects as well as individual applications of thermoresponsive polymers, the underlying structure-property relationships governing the thermoresponse of sterically constrained assemblies, are still poorly understood. Furthermore, the clear majority of publications deals with polymers that exhibit a lower critical solution temperature (LCST) behavior, with PNIPAAM as their main representative. In contrast, for polymer arrangements with an upper critical solution temperature (UCST), there is only limited knowledge about preparation, application and precise physical understanding of the phase transition. This review article provides an overview about the current knowledge of thermoresponsive polymers with limited mobility focusing on UCST behavior and the possibilities for influencing their thermoresponsive switching characteristics. It comprises star polymers, micelles as well as polymer chains grafted to flat substrates and particulate inorganic surfaces. The elaboration of the physicochemical interplay between the architecture of the polymer assembly and the resulting thermoresponsive switching behavior will be in the foreground of this consideration.
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Affiliation(s)
- Patricia Flemming
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany
- Technische Universität Dresden, 01062 Dresden, Germany
| | - Alexander S Münch
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany
| | - Andreas Fery
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany
- Technische Universität Dresden, 01062 Dresden, Germany
| | - Petra Uhlmann
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany
- University of Nebraska-Lincoln, NE 68588, Lincoln, USA
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Kratz C, Furchner A, Sun G, Rappich J, Hinrichs K. Sensing and structure analysis by in situIR spectroscopy: from mL flow cells to microfluidic applications. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:393002. [PMID: 32235045 DOI: 10.1088/1361-648x/ab8523] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 03/31/2020] [Indexed: 06/11/2023]
Abstract
In situmid-infrared (MIR) spectroscopy in liquids is an emerging field for the analysis of functional surfaces and chemical reactions. Different basic geometries exist forin situMIR spectroscopy in milliliter (mL) and microfluidic flow cells, such as attenuated total reflection (ATR), simple reflection, transmission and fiber waveguides. After a general introduction of linear opticalin situMIR techniques, the methodology of ATR, ellipsometric and microfluidic applications in single-reflection geometries is presented. Selected examples focusing on thin layers relevant to optical, electronical, polymer, biomedical, sensing and silicon technology are discussed. The development of an optofluidic platform translates IR spectroscopy to the world of micro- and nanofluidics. With the implementation of SEIRA (surface enhanced infrared absorption) interfaces, the sensitivity of optofluidic analyses of biomolecules can be improved significantly. A large variety of enhancement surfaces ranging from tailored nanostructures to metal-island film substrates are promising for this purpose. Meanwhile, time-resolved studies, such as sub-monolayer formation of organic molecules in nL volumes, become available in microscopic or laser-based set-ups. With the adaption of modern brilliant IR sources, such as tunable and broadband IR lasers as well as frequency comb sources, possible applications of far-field IR spectroscopy inin situsensing with high lateral (sub-mm) and time (sub-s) resolution are considerably extended.
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Affiliation(s)
| | | | - Guoguang Sun
- ISAS-e.V., Schwarzschildstr. 8, 12489 Berlin, Germany
| | - Jörg Rappich
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Kekuléstr. 5, 12489 Berlin, Germany
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Asheghali D, Lee SJ, Furchner A, Gruzd A, Larson S, Tokarev A, Stake S, Zhou X, Hinrichs K, Zhang LG, Minko S. Enhanced neuronal differentiation of neural stem cells with mechanically enhanced touch-spun nanofibrous scaffolds. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2020; 24:102152. [DOI: 10.1016/j.nano.2020.102152] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 12/23/2019] [Accepted: 12/27/2019] [Indexed: 11/29/2022]
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Furchner A, Kratz C, Rappich J, Hinrichs K. Hyperspectral infrared laser polarimetry for single-shot phase-amplitude imaging of thin films. OPTICS LETTERS 2019; 44:4893-4896. [PMID: 31568469 DOI: 10.1364/ol.44.004893] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 08/29/2019] [Indexed: 06/10/2023]
Abstract
We recently presented a novel laser-based infrared (IR) spectroscopic phase-amplitude polarimeter for sub-decisecond and sub-mm2 measurements of organic thin films [Opt. Lett.44, 4387 (2019)OPLEDP0146-959210.1364/OL.44.004387]. Here we report on the hyperspectral-imaging capabilities of this device. The single-shot polarimeter employs a broadly tunable mid-IR (1318-1765 cm-1) quantum cascade laser (QCL) and a four-channel beam-division design for simultaneous phase and amplitude measurements. Fast QCL tuning speeds of up to 1500 cm-1/s enable hyperspectral mapping of large sample areas (50×50 mm2) within several tens of minutes, achieving 120 μm spatial and <0.5 cm-1 spectral resolution. We apply the instrument for imaging both the heterogeneous chemical and structural properties of sub-100 nm thin polymer and fatty-acid films. Our polarimeter opens up new applications regarding laterally resolved IR analyses of complex thin films.
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Furchner A, Kratz C, Hinrichs K. Sub-second infrared broadband-laser single-shot phase-amplitude polarimetry of thin films. OPTICS LETTERS 2019; 44:4387-4390. [PMID: 31465416 DOI: 10.1364/ol.44.004387] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 07/29/2019] [Indexed: 06/10/2023]
Abstract
We report on the first, to the best of our knowledge, sub-second, sub-mm2 infrared (IR) spectroscopic measurements of thin organic films employing a laser-based phase-amplitude polarimeter in reflection geometry. The polarimeter uses a broadband mid-IR quantum cascade laser tunable between 1318 cm-1 and 1765 cm-1, as well as a single-shot beam division scheme for simultaneous single-pulse phase and amplitude measurements. The instrument achieves 120 μm spatial and <0.5 cm-1 spectral resolution, while providing unrivaled performance in terms of acquisition times. Spectral measurements within 100 ms and single-wavelength tracking at 16 μs are now possible. Investigating the vibrational properties accessible in the mid-IR, the polarimeter was applied for monitoring changes in molecular interactions of a 150 nm thin myristic acid film during its thermal phase transition around 55°C.
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Versatile Layer-By-Layer Highly Stable Multilayer Films: Study of the Loading and Release of FITC-Labeled Short Peptide in the Drug Delivery Field. MATERIALS 2019; 12:ma12081206. [PMID: 31013816 PMCID: PMC6514557 DOI: 10.3390/ma12081206] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 04/11/2019] [Accepted: 04/11/2019] [Indexed: 12/14/2022]
Abstract
A viable short FITC-peptide immobilization is the most essential step in the fabrication of multilayer films based on FITC-peptide. These functional multilayer films have potential applications in drug delivery, medical therapy, and so forth. These FITC-peptides films needed to be handled with a lot of care and precision due to their sensitive nature. In this study, a general immobilization method is reported for the purpose of stabilizing various kinds of peptides at the interfacial regions. Utilizing Mesoporous silica nanoparticles can help in the preservation of these FITC-peptides by embedding themselves into these covalently cross-linked multilayers. This basic outlook of the multilayer films is potent enough and could be reused as a positive substrate. The spatio-temporal retention property of peptides can be modulated by varying the number of capping layers. The release speed of guest molecules such as tyrosine within FITC-peptide or/and adamantane (Ad)-in short peptides could also be fine-tuned by the specific arrangements of the multilayers of mesoporous silica nanoparticles (MSNs) and hyaluronic acid- cyclodextrin (HA-CD) multilayer films.
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Furchner A, Walder C, Zellmeier M, Rappich J, Hinrichs K. Broadband infrared Mueller-matrix ellipsometry for studies of structured surfaces and thin films. APPLIED OPTICS 2018; 57:7895-7904. [PMID: 30462056 DOI: 10.1364/ao.57.007895] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 08/14/2018] [Indexed: 06/09/2023]
Abstract
We present a high-optical-throughput infrared Mueller-matrix (MM) ellipsometer for the characterization of structured surfaces and ultrathin films. Its unprecedented sensitivity of about 10-4 in the normalized MM elements enables studies of the complex vibrational fingerprint of thin organic films under different ambient conditions. The ellipsometer acquires quadruples of MM elements within a few 10 s to min, rendering it interesting for process and in-line monitoring. It uses retractable achromatic retarders for increased signal to noise, and tandem wire-grid polarizers for improved polarization control. We demonstrate several scientific and industry-related applications. First, we determine the 3D profile of μm-sized trapezoidal SiO2 gratings on Si from azimuth-dependent MM measurements. Data modeling based on rigorous coupled-wave analysis is employed to quantify grating structure and orientation. We then monitor polymer relaxation processes with a time resolution of 47 s. Measurements of polymer films as thin as 7.7 nm illustrate the sensitivity of the device. We finally couple a liquid flow cell to the ellipsometer, highlighting the prospects for in situ infrared MM studies of thin films at solid-liquid interfaces.
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Kratz C, Furchner A, Oates TWH, Janasek D, Hinrichs K. Nanoliter Sensing for Infrared Bioanalytics. ACS Sens 2018; 3:299-303. [PMID: 29405057 DOI: 10.1021/acssensors.7b00902] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Nondestructive label-free bioanalytics of microliter to nanoliter sample volumes with low analyte concentrations requires novel analytic approaches. For this purpose, we present an optofluidic platform that combines surface-enhanced in situ infrared spectroscopy with microfluidics for sensing of surface-immobilized ultrathin biomolecular films in liquid analytes. Submonolayer sensitivity down to surface densities of few ng/cm2 is demonstrated for the adsorption of the thiolate tripeptide glutathione and for the recognition of streptavidin on a biotinylated enhancement substrate. Nonfunctionalized and functionalized metal island films on planar oxidized silicon substrates are used for signal enhancement with quantifiable enhancement properties. A single-reflection geometry at an incidence angle below the attenuated-total-reflection (ATR) regime is used with ordinary planar, IR-transparent windows. The geometry circumvents the strong IR absorption of common polymer materials and of aqueous environments in the IR fingerprint region. This practice enables straightforward quantitative analyses of, e.g., adsorption kinetics as well as chemical and structural properties in dependence of external stimuli.
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Affiliation(s)
- Christoph Kratz
- Leibniz-Institut für Analytische Wissenschaften − ISAS − e.V., Schwarzschildstr. 8, 12489 Berlin, Germany
| | - Andreas Furchner
- Leibniz-Institut für Analytische Wissenschaften − ISAS − e.V., Schwarzschildstr. 8, 12489 Berlin, Germany
| | - Thomas W. H. Oates
- Leibniz-Institut für Analytische Wissenschaften − ISAS − e.V., Schwarzschildstr. 8, 12489 Berlin, Germany
| | - Dirk Janasek
- Leibniz-Institut für Analytische Wissenschaften − ISAS − e.V., Otto-Hahn-Str. 6b, 44227 Dortmund, Germany
| | - Karsten Hinrichs
- Leibniz-Institut für Analytische Wissenschaften − ISAS − e.V., Schwarzschildstr. 8, 12489 Berlin, Germany
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Ogieglo W, Furchner A, Ghanem B, Ma X, Pinnau I, Wessling M. Mixed-Penetrant Sorption in Ultrathin Films of Polymer of Intrinsic Microporosity PIM-1. J Phys Chem B 2017; 121:10190-10197. [PMID: 29023118 DOI: 10.1021/acs.jpcb.7b10061] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Mixed-penetrant sorption into ultrathin films of a superglassy polymer of intrinsic microporosity (PIM-1) was studied for the first time by using interference-enhanced in situ spectroscopic ellipsometry. PIM-1 swelling and the concurrent changes in its refractive index were determined in ultrathin (12-14 nm) films exposed to pure and mixed penetrants. The penetrants included water, n-hexane, and ethanol and were chosen on the basis of their significantly different penetrant-penetrant and penetrant-polymer affinities. This allowed studying microporous polymer responses at diverse ternary compositions and revealed effects such as competition for the sorption sites (for water/n-hexane or ethanol/n-hexane) or enhancement in sorption of typically weakly sorbing water in the presence of more highly sorbing ethanol. The results reveal details of the mutual sorption effects which often complicate comprehension of glassy polymers' behavior in applications such as high-performance membranes, adsorbents, or catalysts. Mixed-penetrant effects are typically very challenging to study directly, and their understanding is necessary owing to a broadly recognized inadequacy of simple extrapolations from measurements in a pure component environment.
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Affiliation(s)
- Wojciech Ogieglo
- DWI - Leibniz Institute for Interactive Materials , Forckenbeckstr. 50, 52074 Aachen, Germany
| | - Andreas Furchner
- Leibniz-Institute für Analytische Wissenschaften - ISAS - e.V. , Schwarzschildstrasse 8, 12489 Berlin, Germany
| | - Bader Ghanem
- King Abdullah University of Science and Technology (KAUST) , Advanced Membranes and Porous Materials Center (AMPMC), Al-Jazri Building 4, Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Xiaohua Ma
- King Abdullah University of Science and Technology (KAUST) , Advanced Membranes and Porous Materials Center (AMPMC), Al-Jazri Building 4, Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Ingo Pinnau
- King Abdullah University of Science and Technology (KAUST) , Advanced Membranes and Porous Materials Center (AMPMC), Al-Jazri Building 4, Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Matthias Wessling
- DWI - Leibniz Institute for Interactive Materials , Forckenbeckstr. 50, 52074 Aachen, Germany
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Cai J, Xin H, Cheng L, Fu Y, Jiang D, Feng J, Fu Q, Jin Y, Liang X. Preparative separation of the polar part from the rhizomes of Anemarrhena asphodeloides using a hydrophilic C18 stationary phase. J Chromatogr B Analyt Technol Biomed Life Sci 2017; 1063:149-155. [PMID: 28865331 DOI: 10.1016/j.jchromb.2017.08.034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 08/22/2017] [Accepted: 08/24/2017] [Indexed: 11/17/2022]
Abstract
The goal of this study was to develop a method that utilized a hydrophilic C18 stationary phase in the preparative high performance liquid chromatography to isolate the polar part from the rhizomes of Anemarrhena asphodeloides. The results showed that an initial mobile phase of pure water for the separation could greatly increase the retention and solubility of the polar compounds at the preparative scale. Introducing polar groups on the surface of the hydrophilic C18 column together with the use of optimized mobile phase compositions improved the column separation selectivity for polar compounds. Eleven previously undescribed compounds in Anemarrhena asphodeloides were obtained, indicating that the method developed in this study would facilitate the purification and separation of the polar part of traditional Chinese medicines.
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Affiliation(s)
- Jianfeng Cai
- Engineering Research Center of Pharmaceutical Process Chemistry, Ministry of Education, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, PR China
| | - Huaxia Xin
- Engineering Research Center of Pharmaceutical Process Chemistry, Ministry of Education, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, PR China
| | - Lingping Cheng
- Engineering Research Center of Pharmaceutical Process Chemistry, Ministry of Education, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, PR China
| | - YanHui Fu
- Hai Nan Normal University, 99 South Longkun Road, Haikou, 571127, PR China
| | - Dasen Jiang
- Engineering Research Center of Pharmaceutical Process Chemistry, Ministry of Education, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, PR China
| | - Jiatao Feng
- Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical, Physics, Chinese Academy of Science, Dalian 116203, PR China
| | - Qing Fu
- Engineering Research Center of Pharmaceutical Process Chemistry, Ministry of Education, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, PR China.
| | - Yu Jin
- Engineering Research Center of Pharmaceutical Process Chemistry, Ministry of Education, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, PR China
| | - Xinmiao Liang
- Engineering Research Center of Pharmaceutical Process Chemistry, Ministry of Education, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, PR China; Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical, Physics, Chinese Academy of Science, Dalian 116203, PR China
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