all chemicals and reagents were of high performance liquid chromatography ( hplc ) or analytical grade .
pyrrole ( 99  % ) , thiophene ( 99  % ) , and tetrabutylammonium perchlorate ( 98  % ) were purchased from sigma - aldrich ( schnelldorf , germany ) .
medical steel wires ( ni  cr ,   =  750  m ) were purchased from b. braun surgical s.a .
polypyrrole ( ppy ) and polythiophene ( pth ) coatings were synthesized by electropolymerization with a linear sweep voltammetry technique .
the three - electrode cell was filled with electrolyte solution consisting of 100  mm pyrrole / thiophene ( fig .  4 ) and 250  mm tetrabutylammonium perchlorate in acetonitrile.fig . 
4chemical structures of ppy ( a ) and pth ( b ) spme fiber coatings chemical structures of ppy ( a ) and pth ( b ) spme fiber coatings polymerization was performed using medical steel wires as working electrodes . an ag / ag electrode was applied as a reference electrode , with platinum net bent into a cylinder as a counterelectrode . for ppy , a potential range from 0.2 to + 2.5  v and seven scans
second , an additional 14 scans in the higher potential range from 0.2 to 2.7  v were used ( fig . 
5electropolymerization of pyrrole ( a ) and thiophene ( b ) electropolymerization of pyrrole ( a ) and thiophene ( b ) the morphologies of the polypyrrole and polythiophene fibers were investigated using a scanning electron microscope ( leo 1430vp ; carl zeiss smt , oberkochen , germany ) coupled with a backscattered electron ( bse ) detector .
small angle x - ray scattering ( saxs ) data were collected using a nanostar system ( bruker axs gmbh , karlsruhe , germany ) with pinhole collimation and a two - dimensional hi  star detector with resolution of 1,024    1,024 pixels , mounted on an x - ray tube with a copper anode and equipped with crossed gbel focusing mirrors .
samples were mounted between two mica windows in sample holders with thickness of 1 or 2  mm .
the sample - to - detector distance was 650  mm , and the exposure time for a single frame was 10,000  s. each sample was measured three times , and the obtained data were averaged .
the saxs data were recorded within the scattering vector range of 0.15  nm  <  s  <  3.5  nm ( where s  =  4sin/ , 2 is the scattering angle , and  is the x - ray wavelength ) .
the saxs data were corrected for the detector response and normalized to the intensity of the incident beam , and the background scattering ( empty holder ) was subtracted using the saxs_nt  v4.1 program package ( bruker axs gmbh , karlsruhe , germany ) .
electropolymerization was performed using a homemade electrochemical cell coupled with a high performance potentiostat  galvanostat ( pgstat128n series ; metrohm - autolab b.v . ,
all chemicals and reagents were of high performance liquid chromatography ( hplc ) or analytical grade .
pyrrole ( 99  % ) , thiophene ( 99  % ) , and tetrabutylammonium perchlorate ( 98  % ) were purchased from sigma - aldrich ( schnelldorf , germany ) .
medical steel wires ( ni  cr ,   =  750  m ) were purchased from b. braun surgical s.a .
polypyrrole ( ppy ) and polythiophene ( pth ) coatings were synthesized by electropolymerization with a linear sweep voltammetry technique .
the three - electrode cell was filled with electrolyte solution consisting of 100  mm pyrrole / thiophene ( fig .  4 ) and 250  mm tetrabutylammonium perchlorate in acetonitrile.fig . 
4chemical structures of ppy ( a ) and pth ( b ) spme fiber coatings chemical structures of ppy ( a ) and pth ( b ) spme fiber coatings polymerization was performed using medical steel wires as working electrodes . an ag / ag electrode was applied as a reference electrode , with platinum net bent into a cylinder as a counterelectrode . for ppy , a potential range from 0.2 to + 2.5  v and seven scans
second , an additional 14 scans in the higher potential range from 0.2 to 2.7  v were used ( fig . 
5electropolymerization of pyrrole ( a ) and thiophene ( b ) electropolymerization of pyrrole ( a ) and thiophene ( b )
the morphologies of the polypyrrole and polythiophene fibers were investigated using a scanning electron microscope ( leo 1430vp ; carl zeiss smt , oberkochen , germany ) coupled with a backscattered electron ( bse ) detector .
small angle x - ray scattering ( saxs ) data were collected using a nanostar system ( bruker axs gmbh , karlsruhe , germany ) with pinhole collimation and a two - dimensional hi  star detector with resolution of 1,024    1,024 pixels , mounted on an x - ray tube with a copper anode and equipped with crossed gbel focusing mirrors .
samples were mounted between two mica windows in sample holders with thickness of 1 or 2  mm .
the sample - to - detector distance was 650  mm , and the exposure time for a single frame was 10,000  s. each sample was measured three times , and the obtained data were averaged .
the saxs data were recorded within the scattering vector range of 0.15  nm  <  s  <  3.5  nm ( where s  =  4sin/ , 2 is the scattering angle , and  is the x - ray wavelength ) .
the saxs data were corrected for the detector response and normalized to the intensity of the incident beam , and the background scattering ( empty holder ) was subtracted using the saxs_nt  v4.1 program package ( bruker axs gmbh , karlsruhe , germany ) .
 abstractpolymeric polypyrrole and polythiophene solid phase microextraction ( spme ) coatings were prepared using electropolymerization with a linear sweep voltammetry technique . 
 physicochemical properties were measured using different methods , in particular small angle x - ray scattering and scanning electron microscopy . by using innovative approaches for pore size measurement , we were able to calculate a maximum of the pore size range from 80 to 90  nm . additionally , film thicknesses measured from 90 to 150  m . using scanning electron microscopy 
 , we describe the characteristics of polymer growth on the support surface.graphical abstract 
Experimental
Preparation of SPME coatings
Scanning electron microscopy
Small angle X-ray scattering