On PowerShell command pipe to export CSV add Encoding Unicode if characters change to ?
Credit: Idera

execute xp_cmdshell 'powershell -Command "Get-ChildItem -File -Path @path -filter *.* -Recurse | ForEach-Object {[PsCustomObject]@{Fullname = "$($_.FullName)"; LastWriteTime = "$($_.LastWriteTime)"}} | Sort Fullname -Descending | Export-Csv -Path @CSVFile -NoTypeInformation -Encoding unicode"'

If using BULK INSERT ensure widechar is used (It will work but TSQL will add notices which may add pointless text to log files)

BULK INSERT #bcp_file_mem
                FROM @CSVFile
                                WITH (FORMAT = 'CSV', DATAFILETYPE = 'widechar', FIELDQUOTE = '"', FIRSTROW = 2, FIELDTERMINATOR = ',', ROWTERMINATOR = '\n', TABLOCK);