1
|
Effects of Charge Density on Photophysics and Aggregation Behavior of Anionic Fluorene-Arylene Conjugated Polyelectrolytes. Polymers (Basel) 2018; 10:polym10030258. [PMID: 30966293 PMCID: PMC6414976 DOI: 10.3390/polym10030258] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Revised: 02/23/2018] [Accepted: 02/26/2018] [Indexed: 01/19/2023] Open
Abstract
Three anionic fluorene-based alternating conjugated polyelectrolytes (CPEs) have been synthesized that have 9,9-bis(4-phenoxy-butylsulfonate) fluorene-2,7-diyl and 1,4-phenylene (PBS-PFP), 4,4′-biphenylene (PBS-PFP2), or 4,4″-p-terphenylene (PBS-PFP3) groups, and the effect of the length of the oligophenylene spacer on their aggregation and photophysics has been studied. All form metastable dispersions in water, but can be solubilized using methanol, acetonitrile, or dioxane as cosolvents. This leads to increases in their emission intensities and blue shifts in fluorescence maxima due to break-up of aggregates. In addition, the emission maximum shifts to the blue and the loss of vibronic structure are observed when the number of phenylene rings is increased. Debsity Functional Theory (DFT) calculations suggest that this is due to increasing conformational flexibility as the number of phenylene rings increases. This is supported by increasing amplitude in the fast component in the fluorescence decay. The nonionic surfactant n-dodecylpentaoxyethylene glycol ether (C12E5) also breaks up aggregates, as seen by changes in fluorescence intensity and maximum. However, the loss in vibrational structure is less pronounced in this case, possibly due to a more rigid environment in the mixed surfactant-CPE aggregates. Further information on the aggregates formed with C12E5 was obtained by electrical conductivity measurements, which showed an initial increase in specific conductivity upon addition of surfactants, while at higher surfactant/CPE molar ratios a plateau was observed. The specific conductance in the plateau region decreased in the order PBS-PFP3 < PBS-PFP2 < PBS-PFP, in agreement with the change in charge density on the CPE. The reverse process of aggregate formation has been studied by injecting small volumes of solutions of CPEs dissolved at the molecular level in a good solvent system (50% methanol-water) into the poor solvent, water. Aggregation was monitored by changes in both fluorescence and light scattering. The rate of aggregation increases with hydrophobicity and concentration of sodium chloride but is only weakly dependent on temperature.
Collapse
|
2
|
Monteserín M, Burrows HD, Valente AJM, Pais AACC, Di Paolo RE, Maçanita AL, Tapia MJ. Fluorescence Enhancement of a Cationic Fluorene-Phenylene Conjugated Polyelectrolyte Induced by Nonionic n-Alkyl Polyoxyethylene Surfactants. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:13350-13363. [PMID: 29112441 DOI: 10.1021/acs.langmuir.7b02818] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The modulation of conjugated polyelectrolyte fluorescence response by nonionic surfactants is dependent on the structures of the surfactant and polymer, polymer average molecular weight, and polyelectrolyte-surfactant interactions. In this paper, we study the effect of nonionic n-alkyl polyoxyethylene surfactants (CiEj) with different alkyl chain lengths (CiE5 with i = 6, 8, 10, and 12) and number of oxyethylene groups (C12Ej with j = 5, 7, and 9) on the photophysics and ionic conductivity of poly{[9,9-bis(6'-N,N,N-trimethylammonium)-hexyl]-2,7-fluorene-alt-1,4-phenylene}bromide (HTMA-PFP) in dimethyl sulfoxide-water 4% (v/v). Molecular dynamics simulations show that HTMA-PFP chains tend to approach as the simulation evolves. However, the minimum distance between the polymer centers of mass increases upon addition of the surfactant and grows with both the surfactant alkyl chain length and the number of oxyethylene groups, although there are no specific polymer-surfactant interactions. A significant increase in the polymer emission intensity has been observed at surfactant concentrations around their critical micelle concentrations (cmcs), which is attributed to polymer aggregate disruption. However, an increase in the solution conductivity for concentrations above the C12E5 cmc has only been observed for the HTMA-PFP/C12E5 system. The enhancement of fluorescence emission intensity and conductivity upon surfactant addition increases with polymer average molecular weights and seems to be controlled by the polymer-surfactant proximity, which is maximum for C10E5 and C12E5.
Collapse
Affiliation(s)
- María Monteserín
- Departamento de Química, Universidad de Burgos , Plaza Misael Bañuelos, Burgos 09001, Spain
| | - Hugh D Burrows
- Centro de Química de Coimbra (CQC), Department of Chemistry, University of Coimbra , 3004-535 Coimbra, Portugal
| | - Artur J M Valente
- Centro de Química de Coimbra (CQC), Department of Chemistry, University of Coimbra , 3004-535 Coimbra, Portugal
| | - A A C C Pais
- Centro de Química de Coimbra (CQC), Department of Chemistry, University of Coimbra , 3004-535 Coimbra, Portugal
| | - Roberto E Di Paolo
- Departamento de Engenharia Química e Biologica, Instituto Superior Técnico (IST) , Avenida Rovisco Pais, P1049-001 Lisboa, Portugal
| | - Antonio L Maçanita
- Departamento de Engenharia Química e Biologica, Instituto Superior Técnico (IST) , Avenida Rovisco Pais, P1049-001 Lisboa, Portugal
| | - María J Tapia
- Departamento de Química, Universidad de Burgos , Plaza Misael Bañuelos, Burgos 09001, Spain
| |
Collapse
|
3
|
Stewart B, Burrows HD. Molecular Dynamics Study of Self-Assembly of Aqueous Solutions of Poly[9,9-bis(4-Sulfonylbutoxyphenylphenyl) Fluorene-2,7-diyl-2,2'-Bithiophene] (PBS-PF2T) in the Presence of Pentaethylene Glycol Monododecyl Ether (C 12E₅). MATERIALS (BASEL, SWITZERLAND) 2016; 9:E379. [PMID: 28773506 PMCID: PMC5503020 DOI: 10.3390/ma9050379] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Revised: 05/09/2016] [Accepted: 05/10/2016] [Indexed: 01/31/2023]
Abstract
Results are presented using molecular dynamics (MD) of the self-assembly of the conjugated polyelectrolyte poly[9,9-bis(4-sulfonylbutoxyphenylphenyl) fluorene-2,7-diyl-2,2'-bithiophene] (PBS-PF2T) with 680 mM pentaethylene glycol monododecyl ether (C12E₅) in water. Simulations are used to examine the interaction between PBS-PF2T and C12E₅ and suggest a break-up of PBS-PF2T aggregates in solution. These systems are dominated by the formation of cylindrical phases at temperatures between 0 °C and 20 °C and also between 45 °C and 90 °C. More diffuse phases are seen to occur between 20 °C and 45 °C and also above 90 °C. Simulations are related to previous computational and experimental studies on PBS-PF2T aggregation in the presence of tetraethylene glycol monododecyl ether (C12E₄) in bulk and thin films.
Collapse
Affiliation(s)
- Beverly Stewart
- Centro de Química de Coimbra, Chemistry Department, University of Coimbra, Coimbra 3004-535, Portugal.
| | - Hugh Douglas Burrows
- Centro de Química de Coimbra, Chemistry Department, University of Coimbra, Coimbra 3004-535, Portugal.
| |
Collapse
|
4
|
Burrows HD, Valente AJ, Costa T, Stewart B, Tapia MJ, Scherf U. What conjugated polyelectrolytes tell us about aggregation in polyelectrolyte/surfactant systems. J Mol Liq 2015. [DOI: 10.1016/j.molliq.2015.04.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
5
|
Knaapila M, Fonseca SM, Stewart B, Torkkeli M, Perlich J, Pradhan S, Scherf U, Castro RAE, Burrows HD. Nanostructuring of the conjugated polyelectrolyte poly[9,9-bis(4-sulfonylbutoxyphenyl)fluorene-2,7-diyl-2,2'-bithiophene] in liquid crystalline C12E4 in bulk water and aligned thin films. SOFT MATTER 2014; 10:3103-3111. [PMID: 24695747 DOI: 10.1039/c4sm00092g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We report on the conjugated polyelectrolyte 12 mM poly[9,9-bis(4-sulfonylbutoxyphenyl) fluorene-2,7-diyl-2,2'-bithiophene] (PBS-PF2T) mixed in concentrated aqueous 680 mM tetraethylene glycol monododecyl ether (C12E4) in bulk and thin films. A blue-shift in the fluorescence spectrum demonstrates breakup of PBS-PF2T aggregates in bulk aqueous C12E4. Small-angle X-ray scattering data indicate that this mixture follows a very similar phase behaviour to binary mixtures of a pure surfactant with water, including a micellar phase below about 20 °C, a lamellar phase in between about 20 and 70 °C and a proposed coexistence of water and the liquid surfactant solution above 70 °C. Molecular dynamics simulations reproduce these transitions and suggest that PBS-PF2T is incorporated into the surfactant headgroup region, and is, on average, perpendicular to the alkyl chains. In wet thin films, grazing-incidence small-angle X-ray scattering shows that the phase window for the lamellar phase becomes much narrower, located at about 30-34 °C. Weakly ordered phases exist both below and above these temperatures. These phases are isotropic, but lamellae become aligned in a stacked manner on the surface whether approached from low or high temperatures. Dry films are disordered but can be reversibly ordered and disordered and aligned and misaligned by maintaining the temperature at 30-34 °C and switching relative outside humidity between 32% and 100%.
Collapse
Affiliation(s)
- M Knaapila
- Physics Department, Institute for Energy Technology, NO-2027 Kjeller, Norway.
| | | | | | | | | | | | | | | | | |
Collapse
|
6
|
Ostwald ripening of nanoemulsions stopped by combined interfacial adsorptions of molecular and macromolecular nonionic stabilizers. Colloids Surf A Physicochem Eng Asp 2013. [DOI: 10.1016/j.colsurfa.2013.02.028] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
7
|
Marques AT, Burrows HD, Seixas de Melo JS, Valente AJM, Justino LLG, Scherf U, Fron E, Rocha S, Hofkens J, Snedden EW, Monkman AP. Spectroscopic properties, excitation, and electron transfer in an anionic water-soluble poly(fluorene-alt-phenylene)-perylenediimide copolymer. J Phys Chem B 2012; 116:7548-59. [PMID: 22554070 DOI: 10.1021/jp3000703] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
An anionic fluorene-phenylene poly{1,4-phenylene-[9,9-bis(4-phenoxy-butylsulfonate)]fluorene-2,7-diyl}-based copolymer containing on-chain perylenediimine (PDI) chromophoric units, PBS-PFP-PDI, was synthesized and its photophysical properties studied as aggregates and isolated chains in water and dioxane/water (1:1) solution. UV-vis and emission spectroscopy measurements, time-correlated single photon counting, and wide field imaging have been employed to investigate the excited-state behavior of the PBS-PFP-PDI copolymer, including the effect of environment on the energy and electron transfer to the on-chain PDI chromophore. Although the Förster overlap integral is favorable, no evidence is found for intramolecular singlet excitation energy transfer in isolated copolymer chains in solution. Fluorescence is suggested to involve an interchain process, thus revealing that isolated copolymer chains in solution do not undergo efficient intramolecular energy transfer. However, quenching of the PBS-PFP excited state by PDI is observed in aqueous media and ultrafast pump-probe studies in water or dioxane-water solutions show that electron transfer occurs from the phenylene-fluorene units to the PDI. The extent of electron transfer increases with aggregation, suggesting it is largely an interchain process. The interaction of the negatively charged PBS-PFP-PDI copolymer with the positively charged surfactant hexadecyltrimethylammonium bromide (CTAB) in solution has also been studied. The copolymer PBS-PFP-PDI aggregates with the surfactant already at concentrations below the critical micelle concentration (cmc) and the nonpolar environment allows intermolecular energy transfer, observed by the weak emission band located at 630 nm that is associated with the emission of the PDI chromophore. However, the fact that the PDI photoluminescence (PL) lifetime (~1.4 ns) obtained in the presence of CTAB is considerably shorter than that of the nonaggregated chromophore (~5.4 ns) suggests that even in this case there is considerable PL quenching, possibly through some charge transfer route. The increase of the PBS-PFP-PDI photoluminescence intensity at surfactant concentrations above the cmc indicates deaggregation of polyelectrolyte within the initially formed polyelectrolyte-surfactant aggregates.
Collapse
Affiliation(s)
- Ana T Marques
- Department of Chemistry, University of Coimbra, P3004-535 Coimbra, Portugal.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Machado AHE, Lundberg D, Ribeiro AJ, Veiga FJ, Lindman B, Miguel MG, Olsson U. Preparation of calcium alginate nanoparticles using water-in-oil (W/O) nanoemulsions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:4131-41. [PMID: 22296569 DOI: 10.1021/la204944j] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
A procedure for the preparation of calcium alginate nanoparticles in the aqueous phase of water-in-oil (W/O) nanoemulsions was developed. The emulsions were produced from mixtures of the nonionic surfactant tetraethylene glycol monododecyl ether (C(12)E(4)), decane, and aqueous solutions of up to 2 wt % sodium alginate by means of the phase inversion temperature (PIT) emulsification method. This method allows the preparation of finely dispersed emulsions without a large input of mechanical energy. With alginate concentrations of 1-2 wt % in the aqueous phase, emulsions showed good stability against Ostwald ripening and narrow, monomodal distributions of droplets with radii <100 nm. Gelation of the alginate was induced by the addition of aqueous CaCl(2) to the emulsions under stirring, and particles formed were collected using a simple procedure based on extraction of the surfactant on addition of excess oil. The final particles were characterized using cryo-transmission electron microscopy (cryo-TEM) and dynamic light scattering (DLS). They were found to be essentially spherical with a homogeneous interior, and their size was similar to that of the initial emulsion droplets. The herein presented "low-energy" method for preparation of biocompatible nanoparticles has the potential to be used in various applications, e.g., for the encapsulation of sensitive biomacromolecules.
Collapse
Affiliation(s)
- Alexandra H E Machado
- Division of Physical Chemistry, Center for Chemistry and Chemical Engineering, Lund University, Lund, Sweden.
| | | | | | | | | | | | | |
Collapse
|
9
|
Monteserín M, Burrows HD, Mallavia R, Di Paolo RE, Maçanita AL, Tapia MJ. How to change the aggregation in the DNA/surfactant/cationic conjugated polyelectrolyte system through the order of component addition: anionic versus neutral surfactants. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:11705-11714. [PMID: 20518566 DOI: 10.1021/la1011764] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The competitive interaction has been studied between double-stranded DNA (dsDNA), the cationic conjugated polyelectrolyte (CPE) poly[9,9-bis(6-N,N,N-trimethylamonium)hexyl)-fluorene-phenylene)] bromide (HTMA-PFP) and anionic or neutral surfactants (sodium dodecyl sulfonate, SDSu, and n-dodecyl pentaoxyethylene glycol ether, C(12)E(5)) in 4% (v/v) dimethyl sulfoxide (DMSO)-water using UV/visible absorption and fluorescence spectroscopy. Dramatic changes are observed in the spectroscopic behavior of the system depending on the order of addition of the reagents, the surfactant charge, and concentration range. If the neutral C(12)E(5) is added to the HTMA-PFP/dsDNA complex, no significant spectroscopic changes are observed. However, if SDSu is added to the same complex, a dramatic increase of the absorbance and emission intensity is observed for surfactant concentrations above the critical micelle concentration (cmc). In contrast, if dsDNA is added to HTMA-PFP/surfactant systems (with surfactant concentrations above their cmc) no significant changes are observed with SDSu, while a dramatic quenching of polymer emission is observed with C(12)E(5), which can be explained quantitatively in terms of HTMA-PFP/surfactant/DNA complexation and the subsequent polymer aggregation upon charge neutralization. The results are compared with those for the binary systems (HTMA-PFP/DNA and HTMA-PFP/surfactants) and indicate the importance of electrostatic interactions between HTMA-PFP and oppositely charged species in the aggregation processes.
Collapse
Affiliation(s)
- María Monteserín
- Departamento de Química, Universidad de Burgos, Burgos 09001, Spain
| | | | | | | | | | | |
Collapse
|
10
|
Tapia MJ, Montserín M, Valente AJM, Burrows HD, Mallavia R. Binding of polynucleotides to conjugated polyelectrolytes and its applications in sensing. Adv Colloid Interface Sci 2010; 158:94-107. [PMID: 19836007 DOI: 10.1016/j.cis.2009.09.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2009] [Revised: 09/10/2009] [Accepted: 09/24/2009] [Indexed: 12/31/2022]
Abstract
We provide a brief overview of the structural characteristics of the main groups of conjugated polyelectrolytes (CPEs) as well as the methods of synthesis and their behaviour in solution. Their tendency to form aggregates in solution, which is one of the key points to be taken into account for them to be used in polynucleotide sensing, is also considered and the various strategies adopted to avoid it will be discussed. These include the synthetic one (with the incorporation of charged and/or bulky substituents), the use of organic co-solvents and the addition of surfactants. The main physical chemical changes (optical, photophysical, electrical conductivity and viscosity) observed upon direct binding between polynucleotide and CPE, the kind of interactions involved and their applicability in sensing are considered as a function of the CPE structural rigidity. Moreover, more complex devices developed in CPE-polynucleotide sensing with the involvement of additional spectroscopic probes to induce Förster resonant energy transfer processes (FRET) or superquenching phenomena are reviewed. Finally, the main CPE applications in biosensing and the potential use of these systems in understanding DNA compaction and possible extension to the construction of supramolecular oligonucleotide structures are summarized.
Collapse
Affiliation(s)
- Maria J Tapia
- Departamento de Química, Universidad de Burgos, Plaza Misael Bañuelos, Burgos 09001, Spain.
| | | | | | | | | |
Collapse
|
11
|
Liao SC, Lai CS, Yeh DD, Habibur Rahman M, Hsu CS, Chen HL, Chen SA. Supramolecular structures of an amphiphilic hairy-rod conjugated copolymer bearing poly(ethylene oxide) side chain. REACT FUNCT POLYM 2009. [DOI: 10.1016/j.reactfunctpolym.2009.03.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
12
|
Burrows HD, Tapia MJ, Fonseca SM, Pradhan S, Scherf U, Silva CL, Pais AACC, Valente AJM, Schillén K, Alfredsson V, Carnerup AM, Tomsic M, Jamnik A. Solubilization of poly{1,4-phenylene-[9,9-bis(4-phenoxy-butylsulfonate)]fluorene-2,7-diyl} in water by nonionic amphiphiles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:5545-5556. [PMID: 19379013 DOI: 10.1021/la8042044] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In the presence of the nonionic alkyloxyethylene surfactant n-dodecylpentaoxyethylene glycol ether (C12E5), the anionic conjugated polyelectrolyte (CPE) poly{1,4-phenylene-[9,9-bis(4-phenoxy-butylsulfonate)]fluorene-2,7-diyl} (PBS-PFP) dissolves in water, leading to a blue shift in fluorescence and dramatic increases in fluorescence quantum yields above the surfactant critical micelle concentration (cmc). No significant changes were seen with a poly(ethylene oxide) of similar size to the surfactant headgroup, confirming that specific surfactant-polyelectrolyte interactions are important. From UV-visible and fluorescence spectroscopy, dynamic light scattering (DLS), small-angle X-ray scattering (SAXS), cryogenic transmission electron microscopy (cryo-TEM), and electrical conductivity, together with our published NMR and small-angle neutron scattering (SANS) results, we provide a coherent model for this behavior in terms of breakup of PBS-PFP clusters through polymer-surfactant association leading to cylindrical aggregates containing isolated polymer chains. This is supported by molecular dynamics simulations, which indicate stable polymer-surfactant structures and also provide indications of the tendency of C12E5 to break up polymer clusters to form these mixed polymer-surfactant aggregates. Radial electron density profiles of the cylindrical cross section obtained from SAXS results reveal the internal structure of such inhomogeneous species. DLS and cryo-TEM results show that at higher surfactant concentrations the micelles start to grow, possibly partially due to formation of long, threadlike species. Other alkyloxyethylene surfactants, together with poly(propylene glycol) and hydrophobically modified poly(ethylene glycol), also solubilize this polymer in water, and it is suggested that this results from a balance between electrostatic (or ion-dipole), hydrophilic, and hydrophobic interactions. There is a small, but significant, dependence of the emission maximum on the local environment.
Collapse
Affiliation(s)
- Hugh D Burrows
- Departamento de Química, and Faculdáde de Farmácia, Universidade de Coimbra, 3004-535 Coimbra, Portugal.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Burrows HD, Tapia MJ, Fonseca SM, Valente AJM, Lobo VMM, Justino LLG, Qiu S, Pradhan S, Scherf U, Chattopadhyay N, Knaapila M, Garamus VM. Aqueous solution behavior of anionic fluorene-co-thiophene-based conjugated polyelectrolytes. ACS APPLIED MATERIALS & INTERFACES 2009; 1:864-874. [PMID: 20356013 DOI: 10.1021/am800267n] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Two anionic fluorene-thiophene alternating copolymers, poly[9,9-bis(4-sulfonylbutoxyphenyl)fluorene-2,7-diyl-2,5-thienylene] (PBS-PFT) and poly[9,9-bis(4-sulfonylbutoxyphenyl)fluorene-2,7-diyl-2,2'-bithiophene-5,5'-diyl] (PBS-PF2T), have been synthesized and their solution behaviors in water studied by UV-vis absorption spectroscopy, fluorescence, and electrical conductivity and compared with that of the previously studied conjugated polyelectrolyte (CPE) poly[9,9-bis(4-sulfonylbutoxyphenyl)fluorene-2,7-diyl-1,4-phenylene] (PBS-PFP). These conjugated polymers do not form solutions at the molecular level in water but instead form clusters. Information on the structure of these clusters for PBS-PF2T comes from small-angle X-ray and neutron scattering. The relative ease of dispersing the copolymers in water increases with an increase in the number of thiophene rings in these alternating copolymers. Semiempirical calculations on the structure suggest that this results from bending of the chains and increased conformational flexibility, decreasing interchain interactions. These CPEs can be dissolved in water at the molecular level using the nonionic surfactants n-dodecylpentaoxyethylene glycol ether (C12E5) or Triton X-100 to obtain systems with increased photoluminescence quantum yield and increased electrical conductivity that can be solution-processed for potential applications as components of sensory or optoelectronic devices.
Collapse
Affiliation(s)
- Hugh D Burrows
- Departamento de Quimica and Centro de Neurociencias e Biologia Celular, Universidade de Coimbra, 3004-535 Coimbra, Portugal.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Burrows HD, Fonseca SM, Silva CL, Pais AACC, Tapia MJ, Pradhan S, Scherf U. Aggregation of the hairy rod conjugated polyelectrolyte poly{1,4-phenylene-[9,9-bis(4-phenoxybutylsulfonate)]fluorene-2,7-diyl} in aqueous solution: an experimental and molecular modelling study. Phys Chem Chem Phys 2008; 10:4420-8. [DOI: 10.1039/b800773j] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
|