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Csányi E, Hammond DB, Bower B, Johnson EC, Lishchuk A, Armes SP, Dong Z, Leggett GJ. XPS Depth-Profiling Studies of Chlorophyll Binding to Poly(cysteine methacrylate) Scaffolds in Pigment-Polymer Antenna Complexes Using a Gas Cluster Ion Source. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:14527-14539. [PMID: 38954522 PMCID: PMC11256746 DOI: 10.1021/acs.langmuir.4c01361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 06/12/2024] [Accepted: 06/17/2024] [Indexed: 07/04/2024]
Abstract
X-ray photoelectron spectroscopy (XPS) depth-profiling with an argon gas cluster ion source (GCIS) was used to characterize the spatial distribution of chlorophyll a (Chl) within a poly(cysteine methacrylate) (PCysMA) brush grown by surface-initiated atom-transfer radical polymerization (ATRP) from a planar surface. The organization of Chl is controlled by adjusting the brush grafting density and polymerization time. For dense brushes, the C, N, S elemental composition remains constant throughout the 36 nm brush layer until the underlying gold substrate is approached. However, for either reduced density brushes (mean thickness ∼20 nm) or mushrooms grown with reduced grafting densities (mean thickness 6-9 nm), elemental intensities decrease continuously throughout the brush layer, because photoelectrons are less strongly attenuated for such systems. For all brushes, the fraction of positively charged nitrogen atoms (N+/N0) decreases with increasing depth. Chl binding causes a marked reduction in N+/N0 within the brushes and produces a new feature at 398.1 eV in the N1s core-line spectrum assigned to tetrapyrrole ring nitrogen atoms coordinated to Zn2+. For all grafting densities, the N/S atomic ratio remains approximately constant as a function of brush depth, which indicates a uniform distribution of Chl throughout the brush layer. However, a larger fraction of repeat units bound to Chl is observed at lower grafting densities, reflecting a progressive reduction in steric congestion that enables more uniform distribution of the bulky Chl units throughout the brush layer. In summary, XPS depth-profiling using a GCIS is a powerful tool for characterization of these complex materials.
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Affiliation(s)
- Evelin Csányi
- Department
of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, U.K.
- Institute
of Materials Research and Engineering, A*STAR
(Agency for Science, Technology and Research), 2 Fusionopolis Way, #08-03 Innovis, 138634 Singapore
| | - Deborah B. Hammond
- Department
of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, U.K.
| | - Benjamin Bower
- Department
of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, U.K.
| | - Edwin C. Johnson
- Department
of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, U.K.
| | - Anna Lishchuk
- Department
of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, U.K.
| | - Steven P. Armes
- Department
of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, U.K.
| | - Zhaogang Dong
- Institute
of Materials Research and Engineering, A*STAR
(Agency for Science, Technology and Research), 2 Fusionopolis Way, #08-03 Innovis, 138634 Singapore
| | - Graham J. Leggett
- Department
of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, U.K.
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Shi X, Wang L, Yan N, Wang Z, Guo L, Steinhart M, Wang Y. Fast Evaporation Enabled Ultrathin Polymer Coatings on Nanoporous Substrates for Highly Permeable Membranes. Innovation (N Y) 2021; 2:100088. [PMID: 34557742 PMCID: PMC8454551 DOI: 10.1016/j.xinn.2021.100088] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 01/31/2021] [Indexed: 11/18/2022] Open
Abstract
Thin polymer coatings covering on porous substrates are a common composite structure required in numerous applications, including membrane separation, and there is a strong need to push the coating thicknesses down to the nanometer scale to maximize the performances. However, producing such ultrathin polymer coatings in a facile and efficient way remains a big challenge. Here, uniform ultrathin polymer covering films (UPCFs) are realized by a facile and general approach based on rapid solvent evaporation. By fast evaporating dilute polymer solutions spread on the surface of porous substrates, we obtain ultrathin coatings (down to ∼30 nm) exclusively on the top surface of porous substrates, forming UPCFs with a block copolymer of polystyrene-block-poly(2-vinyl pyridine) at room temperature or a homopolymer of poly(vinyl alcohol) (PVA) at elevated temperatures. Upon selective swelling of the block copolymer and crosslinking of PVA, we obtain highly permeable membranes delivering ∼2–10 times higher permeance in ultrafiltration and pervaporation than state-of-the-art membranes with comparable selectivities. We have invented a very convenient but highly efficient process for the direct preparation of defective-free ultrathin coatings on porous substrates, which is extremely desired in different fields in addition to membrane separation. Fast solvent evaporation is developed to produce UPCFs on porous substrates Selective swelling to cavitate block copolymers to form interconnected mesopores UPCFs enable the preparation of highly permeable membranes
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Affiliation(s)
- Xiansong Shi
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing, Jiangsu 211816, P.R. China
| | - Lei Wang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing, Jiangsu 211816, P.R. China
| | - Nina Yan
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing, Jiangsu 211816, P.R. China
| | - Zhaogen Wang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing, Jiangsu 211816, P.R. China
| | - Leiming Guo
- Institut für Chemie neuer Materialien, Universität Osnabrück, Barbarastr. 7, 49069 Osnabrück, Germany
| | - Martin Steinhart
- Institut für Chemie neuer Materialien, Universität Osnabrück, Barbarastr. 7, 49069 Osnabrück, Germany
- Corresponding author
| | - Yong Wang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing, Jiangsu 211816, P.R. China
- Corresponding author
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Sree Hari PD, Bakli C, Chakraborty S. Fractional separation of polymers in nanochannels: Combined influence of wettability and structure. ACTA ACUST UNITED AC 2016. [DOI: 10.1002/polb.24122] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- P. D. Sree Hari
- Department of Mechanical Engineering; Indian Institute of Technology Kharagpur; Kharagpur 721302 India
| | - Chirodeep Bakli
- Department of Mechanical Engineering; Indian Institute of Technology Kharagpur; Kharagpur 721302 India
| | - Suman Chakraborty
- Department of Mechanical Engineering; Indian Institute of Technology Kharagpur; Kharagpur 721302 India
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Controlling the thickness of electrochemically produced porous alumina membranes: the role of the current density during the anodization. J APPL ELECTROCHEM 2014. [DOI: 10.1007/s10800-014-0680-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Nunnery GA, Jacob KI, Tannenbaum R. Reactive adsorption of PS-PMMA block copolymers on concave alumina surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:14960-14967. [PMID: 23009166 DOI: 10.1021/la303216n] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The influence of pore size, relative block size, and solvent quality on the extent of diblock copolymer adsorption on alumina surfaces was determined. To this end, the block copolymer that was chosen was poly(styrene)-b-poly(methyl methacrylate) (PS-b-PMMA), in which the PMMA block strongly chemisorbs to the surface and the PS block weakly physisorbs. Several architectures (i.e., different ratios of M(n(PMMA)) and M(n)((PS))) of the PS-b-PMMA copolymers were adsorbed from various solvents onto porous alumina membranes with various pore sizes. It was determined that the diblock copolymer coverage decreased significantly as the pore size decreased, similar to the behavior of the PMMA homopolymer under the same conditions. However, the coverage decreased as the molecular weight of the anchoring block (PMMA) increased for all pore sizes, which is in contrast to the behavior of the PMMA homopolymer under the same conditions. The dependence of the coverage on the relative block size and solvent quality is analyzed on the basis of the anchor-buoy model and the deviation from it in a nonideal system. The results presented in this work are relevant to the study of block copolymer conformation in solutions and on surfaces, adsorption chromatography, and solvent sensors and controls.
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Affiliation(s)
- Grady A Nunnery
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
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Du K, Gan Z. Cellular interactions on hierarchical poly(ε-caprolactone) nanowire micropatterns. ACS APPLIED MATERIALS & INTERFACES 2012; 4:4643-4650. [PMID: 22873768 DOI: 10.1021/am301013e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A double template method to fabricate poly(ε-caprolactone) (PCL) hierarchical patterned nanowires with highly ordered nano- and microscaled topography was developed in this study. The topography of PCL film with a patterned nanowire surface can be easily and well controlled by changing the template and melting time of PCL film on the templates. The surface morphology, water contact angle, protein adsorption, and cell growth behavior on the PCL films with different surface structures were well studied. The results revealed that the PCL nanowire arrays and the hierarchical patterned nanowires showed higher capability of protein adsorption and better cell growth than the PCL film with smooth surface. Typically, the PCL surface with hierarchical nanowire patterns was most favorable for cell attachment and proliferation. The present study was innovative at fabrication of polymer substrates with hierarchical architecture of nanowires inside microscaled islands to gain insight into the cell response to this unique topography and to develop a new method of constructing the bionic surface for tissue engineering applications.
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Affiliation(s)
- Ke Du
- The CAS Key Laboratory of Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing 100190, China
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